Comment #1Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Comment Intent: ObjectionComment Type: GeneralComment: The Definition for Drain Water Heat Exchangers references a standard that only covers a subset of drain water heat exchangers and excludes other technologies. Specifically it excludes IAPMO standard PS 92 2012 and any heat exchangers that we designed to be mounted horizontally. A competing technology exists that has been developed by my company. This technology was independently tested for performance by the FISHNICK food service technology center and certified for installation by IAPMO. We have completed installations in homes in California, Vermont, Connecticut, and Massechutsetts to date. Proposed Change: Drain Water Heat Recovery (DWHR) – A heat exchanger unit that uses outgoing warm drain water to pre - heat incoming cold freshwater, is rated for efficiency and pressure loss according to CSA B55.1, and complies with CSA B55.2. Or complies with IAPMO Standard PS-92-2012. Add new Normative References to Section 6 CSA B55.1 - 12, (2012). “Test method for measuring efficiency and pressure loss of drain water heat recovery units.” CSA Group, Mississauga, Ontari o, Canada L4W 5N6. CSA B55.2 - 12, (2012). “Drain water heat recovery units.” CSA Group, Mississauga, Ontario, Canada L4W 5N6. IAPMO PS-92-2012 Response: Rejected Reason: IAPMO PS 92-2012 does not prescribe an efficiency/effectiveness heat exchanger test procedure for DWHR. While CSA B55.1.12 does prescribe efficiency/effectiveness test protocol for heat exchanger, the protocol is limited to vertical DWHR and horizontal or near horizontal would not qualify. Until the horizontal drain water heat recovery units are included in the scope of CSA B55.1, the RESNET Standard cannot address their effectiveness.
The Definition for Drain Water Heat Exchangers references a standard that only covers a subset of drain water heat exchangers and excludes other technologies. Specifically it excludes IAPMO standard PS 92 2012 and any heat exchangers that we designed to be mounted horizontally. A competing technology exists that has been developed by my company. This technology was independently tested for performance by the FISHNICK food service technology center and certified for installation by IAPMO. We have completed installations in homes in California, Vermont, Connecticut, and Massechutsetts to date.
Drain Water Heat Recovery (DWHR) – A heat exchanger unit that uses outgoing warm drain water to pre - heat incoming cold freshwater, is rated for efficiency and pressure loss according to CSA B55.1, and complies with CSA B55.2. Or complies with IAPMO Standard PS-92-2012.
Add new Normative References to Section 6
CSA B55.1 - 12, (2012). “Test method for measuring efficiency and pressure loss of drain water heat recovery units.” CSA Group, Mississauga, Ontari o, Canada L4W 5N6. CSA B55.2 - 12, (2012). “Drain water heat recovery units.” CSA Group, Mississauga, Ontario, Canada L4W 5N6.
IAPMO PS-92-2012
Rejected
Reason: IAPMO PS 92-2012 does not prescribe an efficiency/effectiveness heat exchanger test procedure for DWHR. While CSA B55.1.12 does prescribe efficiency/effectiveness test protocol for heat exchanger, the protocol is limited to vertical DWHR and horizontal or near horizontal would not qualify. Until the horizontal drain water heat recovery units are included in the scope of CSA B55.1, the RESNET Standard cannot address their effectiveness.
Comment #2Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Comment Intent: ObjectionComment Type: TechnicalComment: In the addendum BSR/RESNET Addendum ‘a’ to ANSI/RESNET 301-2014, it is stated that "Drain Water Heat Recovery (DWHR) – A heat exchanger unit that uses outgoing warm drain water to pre-heat incoming cold freshwater, is rated for efficiency and pressure loss according to CSA B55.1, and complies with CSA B55.2." By requiring compliance specifically to CSA B55.1 and B55.2 the addendum pre-empts the inclusion of Horizontally oriented DWHRS already in use in the market place, eg Ecodrain (see.www.ecodrain.com) . This product has been successfuly tested and certified to IAMPO requirements, NSF 61 conformance and Pb-free certification. The Ecodrain Horizontal DWHR is a unique product that has been developed after several years of Research and Development, and is double wall compliant, and is easily rated at a higher level of efficiency than the Vertical Product, around which the CSA B55.1 has been framed. It is essential that the horizontal product Ecodrain, is also included in the new addendum. As a developer of the product, I feel it would amount to an exclusionary manouevre to exclude the horizontal product from this otherwise valuable addendum. Respectfully, Rana Bose, PEng Proposed Change: Add in an appropriate section, " The DWHR installation can include orientations other than strictly vertical, while meeting all other requirements of the standard." Response: Rejected Reason: While CSA B55.1.12 does prescribe efficiency/effectiveness test protocol for heat exchanger, the protocol is limited to vertical DWHR and horizontal or near horizontal would not qualify. Until the horizontal drain water heat recovery units are included in the scope of CSA B55.1, the RESNET Standard cannot address their effectiveness.
In the addendum BSR/RESNET Addendum ‘a’ to ANSI/RESNET 301-2014, it is stated that "Drain Water Heat Recovery (DWHR) – A heat exchanger unit that uses outgoing warm drain water to pre-heat incoming cold freshwater, is rated for efficiency and pressure loss according to CSA B55.1, and complies with CSA B55.2."
By requiring compliance specifically to CSA B55.1 and B55.2 the addendum pre-empts the inclusion of Horizontally oriented DWHRS already in use in the market place, eg Ecodrain (see.www.ecodrain.com) . This product has been successfuly tested and certified to IAMPO requirements, NSF 61 conformance and Pb-free certification.
The Ecodrain Horizontal DWHR is a unique product that has been developed after several years of Research and Development, and is double wall compliant, and is easily rated at a higher level of efficiency than the Vertical Product, around which the CSA B55.1 has been framed. It is essential that the horizontal product Ecodrain, is also included in the new addendum. As a developer of the product, I feel it would amount to an exclusionary manouevre to exclude the horizontal product from this otherwise valuable addendum.
Respectfully,
Rana Bose, PEng
Add in an appropriate section, " The DWHR installation can include orientations other than strictly vertical, while meeting all other requirements of the standard."
Reason: While CSA B55.1.12 does prescribe efficiency/effectiveness test protocol for heat exchanger, the protocol is limited to vertical DWHR and horizontal or near horizontal would not qualify. Until the horizontal drain water heat recovery units are included in the scope of CSA B55.1, the RESNET Standard cannot address their effectiveness.
Comment #3Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Comment Intent: ObjectionComment Type: GeneralComment: I am in total disagreement with consideration of any DWHR systems. To begin with, energy consumption for hot water has historically been a small part of the overall energy use of a residence. These system heat recovery efficiencies are not the best, and you must also consider the losses back to the hot water supply. By the time the water has reached the drain it has cooled, the amount of heat capable of being transferred is minimal due to the small temperature difference and the types of heat exchangers, and the proportion of overall energy used by the hot water system is small. Theses systems must have a small effect on the overall rating. The rating should not be clouded with the small energy recovery offered by these systems. They should only be considered once they are rated by a third party, similar to our HVAC via AHRI, or HRV's and ERV's via HVI. Don't rely on the manufacturer's to provide us with efficiency data on these systems. On the other hand, inefficient systems, such as recirculating sytems which increase the overall loss of hot water heat, should be considered, but again, only on a minimal basis, and from third party science. Response: Rejected Reason: Commenter does not provide or reference any supporting technical evidence to support opposing the inclusion of DWHR in the standard.
I am in total disagreement with consideration of any DWHR systems. To begin with, energy consumption for hot water has historically been a small part of the overall energy use of a residence. These system heat recovery efficiencies are not the best, and you must also consider the losses back to the hot water supply.
By the time the water has reached the drain it has cooled, the amount of heat capable of being transferred is minimal due to the small temperature difference and the types of heat exchangers, and the proportion of overall energy used by the hot water system is small. Theses systems must have a small effect on the overall rating.
The rating should not be clouded with the small energy recovery offered by these systems. They should only be considered once they are rated by a third party, similar to our HVAC via AHRI, or HRV's and ERV's via HVI.
Don't rely on the manufacturer's to provide us with efficiency data on these systems.
On the other hand, inefficient systems, such as recirculating sytems which increase the overall loss of hot water heat, should be considered, but again, only on a minimal basis, and from third party science.
Reason: Commenter does not provide or reference any supporting technical evidence to support opposing the inclusion of DWHR in the standard.
Comment #4Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Equation 4.2-13Comment Intent: Not an ObjectionComment Type: EditorialComment: No definition is provided for the term bFrac Proposed Change: add definition of bFrac Response: Accepted as modified Reason: The term ‘bFrac’ is a typographical mistake and should have been ‘oFrac’ which is defined. The term has been changed to reflect correction of the typographical error. (see also the response to Comment #15)
No definition is provided for the term bFrac
add definition of bFrac
Accepted as modified
Reason: The term ‘bFrac’ is a typographical mistake and should have been ‘oFrac’ which is defined. The term has been changed to reflect correction of the typographical error. (see also the response to Comment #15)
Comment #5Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 2Comment Intent: Not an ObjectionComment Type: GeneralComment: I'd like to see a user-input for the tank temperature. Perhaps give the filled-in default as 125 (pretty typical), but sometimes we see them much higher - 140 - and that would surely affect energy consumption. If we could change it, we could also show savings by turning back tank temperatures. Regarding water use, there should be an option for no dishwasher or clothes washer, which are common occurrances in affordable housing. If there were no dishwasher, then kitchen sink usage should go up. If there were no clothes washer, assume washing clothes off-site, so then that's somebody else's energy load. I've noticed problems in the existing calculations when trying to compensate for homes without these two features. The inlet temperature should be adjusted seasonally and by location. It could be automaticaly determined by climate location. For example, all climate locations in CZ 4 could be assigned something like 55 degrees in the winter, 65 degrees in the summer, and some sort of mixing in the shoulder seasons. I'm sure water is much warmer in CZ 1 and colder in CZ 5, but there can't be much difference between Baltimore, MD and Washington, DC. Response: Rejected Reason: Allowing ratings to modify the standard operating conditions of the Rated home would constitute the rating of a lifestyle, which would be inconsistent with RESNET’s asset ratings methodology. Creating additional options for homes without clothes washers and dishwashers would severely complicate the proposed hot water use procedure and would also constitute a rating of lifestyle. As the commenter states, homes without dishwashers actually use more hot water than those with dishwashers and homes without clothes washers use that hot water at another location. As to inlet temperature adjustments, that is being accomplished in the Addendum through the required calculation of Tmains in the governing equations for hot water use (equation 4.2-2).
I'd like to see a user-input for the tank temperature. Perhaps give the filled-in default as 125 (pretty typical), but sometimes we see them much higher - 140 - and that would surely affect energy consumption. If we could change it, we could also show savings by turning back tank temperatures.
Regarding water use, there should be an option for no dishwasher or clothes washer, which are common occurrances in affordable housing. If there were no dishwasher, then kitchen sink usage should go up. If there were no clothes washer, assume washing clothes off-site, so then that's somebody else's energy load. I've noticed problems in the existing calculations when trying to compensate for homes without these two features.
The inlet temperature should be adjusted seasonally and by location. It could be automaticaly determined by climate location. For example, all climate locations in CZ 4 could be assigned something like 55 degrees in the winter, 65 degrees in the summer, and some sort of mixing in the shoulder seasons. I'm sure water is much warmer in CZ 1 and colder in CZ 5, but there can't be much difference between Baltimore, MD and Washington, DC.
Reason: Allowing ratings to modify the standard operating conditions of the Rated home would constitute the rating of a lifestyle, which would be inconsistent with RESNET’s asset ratings methodology. Creating additional options for homes without clothes washers and dishwashers would severely complicate the proposed hot water use procedure and would also constitute a rating of lifestyle. As the commenter states, homes without dishwashers actually use more hot water than those with dishwashers and homes without clothes washers use that hot water at another location. As to inlet temperature adjustments, that is being accomplished in the Addendum through the required calculation of Tmains in the governing equations for hot water use (equation 4.2-2).
Comment #6Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Paragraph / Figure / Table / Note: 3.2Comment Intent: ObjectionComment Type: TechnicalComment: IAPMO PS 92-2013, Heat Exchangers and Indirect Water Heaters, is a recognized industry standard and hsould be added as a valid option. Response: Rejected Reason: IAPMO PS 92-2012 does not prescribe an efficiency/effectiveness heat exchanger test procedure for DWHR. As such this IAPMO standard is not relevant to the procedures contained in the proposed addendum. RESNET does not incorporate reference standards unless they are relevant to the provisions of RESNET Standards.
IAPMO PS 92-2013, Heat Exchangers and Indirect Water Heaters, is a recognized industry standard and hsould be added as a valid option.
Reason: IAPMO PS 92-2012 does not prescribe an efficiency/effectiveness heat exchanger test procedure for DWHR. As such this IAPMO standard is not relevant to the procedures contained in the proposed addendum. RESNET does not incorporate reference standards unless they are relevant to the provisions of RESNET Standards.
Comment #7Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Paragraph / Figure / Table / Note: 3.2Comment Intent: ObjectionComment Type: TechnicalComment: IAPMO PS 92-2013, Heat Exchangers and Indirect Water Heaters, is a recognized industry standard and hsould be added as a valid option. Response: Rejected Reason: IAPMO PS 92-2012 does not prescribe an efficiency/effectiveness heat exchanger test procedure for DWHR. As such this IAPMO standard is not relevant to the procedures contained in the proposed addendum. RESNET does not incorporate reference standards unless they are relevant to the provisions of RESNET Standards.
Comment #8Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 5Paragraph / Figure / Table / Note: table 4.2.2.5.2.11(6)Comment Intent: ObjectionComment Type: TechnicalComment: I am raising concerns related to the apparent credits offered for demand recirculation systems as shown in this table. Although I support demand recirculation as viable method to reduce water waste (and by far the most efficient of the various recirculation strategies), i have yet to see demonstrated, comprehensive performance data that suggests that these systems will consistently save distribution system energy relative to conventional non-recirculation strategies. I have worked on residential hot water issues for over 20 years at Davis Energy Group including field monitoring activities, detailed distribution system modeling, and being intimately involved in the development of water heating modeling methodologies for California's Title 24 Building Energy Code. Given the dearth of robust independent field data on demand recirculation performance, and our first-hand experiences with two detailed hot water distribution modeling tools (HWSIM and TRNSYS), I would suggest that you revisit the credits shown in this Table. My initial proposal would be that the demand recirculation with manual control and > R-3 pipe insulation be set at a level equal to the standard system (32) and that the other recirculation systems be rated at an energy level appropriately higher than that level. I believe a cautious approach is warranted until there is sufficient data to clearly document performance. Regards Response: Accepted Gary Klein, the commenter and Philip Fairey discussed this matter and Gary is conducting tests to verify these values. Accepting the commenters change will result in another 30 day review and allow time for the tests. By changing the values in accordance with the commenter’s request, the manual demand control system will still save approximately 14% of hot water use due to the reduction in HWgpd that it causes.
I am raising concerns related to the apparent credits offered for demand recirculation systems as shown in this table. Although I support demand recirculation as viable method to reduce water waste (and by far the most efficient of the various recirculation strategies), i have yet to see demonstrated, comprehensive performance data that suggests that these systems will consistently save distribution system energy relative to conventional non-recirculation strategies.
I have worked on residential hot water issues for over 20 years at Davis Energy Group including field monitoring activities, detailed distribution system modeling, and being intimately involved in the development of water heating modeling methodologies for California's Title 24 Building Energy Code. Given the dearth of robust independent field data on demand recirculation performance, and our first-hand experiences with two detailed hot water distribution modeling tools (HWSIM and TRNSYS), I would suggest that you revisit the credits shown in this Table. My initial proposal would be that the demand recirculation with manual control and > R-3 pipe insulation be set at a level equal to the standard system (32) and that the other recirculation systems be rated at an energy level appropriately higher than that level.
I believe a cautious approach is warranted until there is sufficient data to clearly document performance.
Regards
Accepted
Gary Klein, the commenter and Philip Fairey discussed this matter and Gary is conducting tests to verify these values. Accepting the commenters change will result in another 30 day review and allow time for the tests. By changing the values in accordance with the commenter’s request, the manual demand control system will still save approximately 14% of hot water use due to the reduction in HWgpd that it causes.
Comment #9Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: Page 4, 4.2.2.5.2.11.1Comment Intent: Not an ObjectionComment Type: GeneralComment: This comment is made to express my support for including DWHR and recommend that the CSA 551.1 and 55.2 standards be retained as criteria. The reference to these standards and the labelling required has resulted in excellent compliance to the Ontario Building Code where these products have been referenced since March 2013. Our experience in modelling and in the field is that these units are both effective and cost-efficient as they tend to increase the effective capacity of the water heater as well as recovering energy. Although there may be plumbing certification standards which could be considered to be equivalent to CSA 55.2, I am not aware of other certification standards which set out the efficiency rating method, testing & labelling requirements as does CSA 55.1. I understand that the noted CSA Standards have also been referenced in IECC2015 for DWHR units in commercial buildings. Response: Accepted Reason: Supportive comment requesting no change in the provisions of the proposed standard.
This comment is made to express my support for including DWHR and recommend that the CSA 551.1 and 55.2 standards be retained as criteria. The reference to these standards and the labelling required has resulted in excellent compliance to the Ontario Building Code where these products have been referenced since March 2013. Our experience in modelling and in the field is that these units are both effective and cost-efficient as they tend to increase the effective capacity of the water heater as well as recovering energy.
Although there may be plumbing certification standards which could be considered to be equivalent to CSA 55.2, I am not aware of other certification standards which set out the efficiency rating method, testing & labelling requirements as does CSA 55.1.
I understand that the noted CSA Standards have also been referenced in IECC2015 for DWHR units in commercial buildings.
Reason: Supportive comment requesting no change in the provisions of the proposed standard.
Comment #10Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Paragraph / Figure / Table / Note: Sec. 4.2.2.5.1.4 - Eq. 4.2-2Comment Intent: Not an ObjectionComment Type: EditorialComment: The variable CAPw is defined but not used anywhere in the equation for Reference Home dishwasher hot water use per day. Proposed Change: CAPw = clothes washer capacity in cubic feet Response: Accepted Reason: Editorial revision to strike typographical error of a left-over definition that is no longer used in the Addendum.
The variable CAPw is defined but not used anywhere in the equation for Reference Home dishwasher hot water use per day.
CAPw = clothes washer capacity in cubic feet
Reason: Editorial revision to strike typographical error of a left-over definition that is no longer used in the Addendum.
Comment #11Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 1Paragraph / Figure / Table / Note: Sec. 4.2.2.5.1.4 - Eq. 4.2-2Comment Intent: Not an ObjectionComment Type: EditorialComment: There's a small grammatical typo in this section: "Where5". Proposed Change: Where5 Where Response: Accepted Reason: Editorial correction of typographical error.
There's a small grammatical typo in this section: "Where5".
Where5 Where
Reason: Editorial correction of typographical error.
Comment #12Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Sec. 4.2.2.5.2.11 - Eq. 4.2-11Comment Intent: Not an ObjectionComment Type: EditorialComment: There is a typo in the definition of terms for this equation. "refFgdp" should be changed to "refFgpd." Proposed Change: [4.2.2.5.2.11] refFgdp refFgpd = reference climate-normalized daily fixture water use calculated in accordance with Section 4.2.2.5.1.4 Response: Accepted Reason: Editorial correction of typographical error.
There is a typo in the definition of terms for this equation. "refFgdp" should be changed to "refFgpd."
[4.2.2.5.2.11] refFgdp refFgpd = reference climate-normalized daily fixture water use calculated in accordance with Section 4.2.2.5.1.4
Comment #13Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Sec. 4.2.2.5.2.12 - Eq. 4.2-12Comment Intent: Not an ObjectionComment Type: EditorialComment: There is a typo in the terms defined for this equation. "oWgdp" should be changed to "oWgpd." Proposed Change: [4.2.2.5.2.12] oWgdp oWgpd = daily standard operating condition waste hot water quantity Response: Accepted Reason: Editorial correction of typographical error.
There is a typo in the terms defined for this equation. "oWgdp" should be changed to "oWgpd."
[4.2.2.5.2.12] oWgdp oWgpd = daily standard operating condition waste hot water quantity
Comment #14Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Sec. 4.2.2.5.2.13 - Eq. 4.2-13Comment Intent: Not an ObjectionComment Type: EditorialComment: For improved readability, align the indenting of the definitions for the following terms: "CFA", "Nfl", and "Bsmt". Proposed Change: [4.2.2.5.2.13] where CFA = conditioned floor area Nfl = number of conditioned floor levels in the residence, including conditioned basements Bsmt = presence =1.0 or absence = 0.0 of an unconditioned basement in the residence Response: Accepted Reason: Editorial correction of formatting
For improved readability, align the indenting of the definitions for the following terms: "CFA", "Nfl", and "Bsmt".
[4.2.2.5.2.13] where CFA = conditioned floor area Nfl = number of conditioned floor levels in the residence, including conditioned basements Bsmt = presence =1.0 or absence = 0.0 of an unconditioned basement in the residence
Reason: Editorial correction of formatting
Comment #15Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Eq. 4.2-13Comment Intent: Not an ObjectionComment Type: EditorialComment: In this equation, the term "bFrac" should be changed to "oFrac". In addition, a definition should be added for this term. Proposed Change: sWgpd = (refWgpd – refWgpd * bFrac oFrac) * pRatio * sysFactor Where sWgpd = daily structural waste hot water quantity refWgpd = reference climate-normalized distribution system waste water use calculated in accordance with Section 4.2.2.5.1.4 oFrac = 0.25 = fraction of hot water waste from standard operating conditions Response: Accepted Reason: Editorial correction of typographical error.
In this equation, the term "bFrac" should be changed to "oFrac". In addition, a definition should be added for this term.
sWgpd = (refWgpd – refWgpd * bFrac oFrac) * pRatio * sysFactor
Where
sWgpd = daily structural waste hot water quantity
refWgpd = reference climate-normalized distribution system waste water use calculated in accordance with Section 4.2.2.5.1.4
oFrac = 0.25 = fraction of hot water waste from standard operating conditions
Comment #16Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 5Paragraph / Figure / Table / Note: Sec. 4.2.2.5.2.11.2 - Eq. 4.2 -17Comment Intent: Not an ObjectionComment Type: EditorialComment: “Eq. 4.1-17” is mislabeled and should be labeled as "Eq. 4.2-17.” It is correctly referred to as “Eq. 4.2-17” on the line prior to the equation. Proposed Change: [4.2.2.5.2.11.2] Ewaste = oEWfact * (1-oCDeff) + sEWfact * pEratio Eq. 4.1-17 Eq. 4.2-17 Response: Accepted Reason: Editorial correction of typographical error.
“Eq. 4.1-17” is mislabeled and should be labeled as "Eq. 4.2-17.” It is correctly referred to as “Eq. 4.2-17” on the line prior to the equation.
[4.2.2.5.2.11.2] Ewaste = oEWfact * (1-oCDeff) + sEWfact * pEratio Eq. 4.1-17 Eq. 4.2-17
Comment #17Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 6Paragraph / Figure / Table / Note: Equation 6Comment Intent: Not an ObjectionComment Type: TechnicalComment: Can you please clarify whether the hot water operational control devices will include both those for sinks as well as those for showers? Or any other types? I am aware of devices for showers (a well known product is called ShowerStart) and also motion, touch or pedal operated faucets. The intent of such devices is to reduce the waste of water, either while waiting for hot water to arrive a a shower or in the case of the faucet control during the use periods at the sink. Equation 6 shows the potential for the inclusion of such devices as CDeff (see excerpt below). oWgpd = refWgpd * oFrac * (1-oCDeff) where oWgpd = daily operational hot water waste quantity oFrac = 0.25 = fraction of hot water waste attributable to standard operating conditions (see above discussion) oCDeff = 0.0 (until specific Hot Water Operational Control Devices have been approved) As shown, it appears that there can only be one such factor. However, if a faucet has an operational control, it is likely to have both a different factor and will impact a different number of gallons. CDeff also appears in Equation 9. The same concern applies in both cases. I think that the method should be flexible enough to account for any approved operational control device. Response: Rejected Reason: This is covered by the provisions of the standard by requiring that such devices be approved, with the meaning of “approved” provided by Section 3 of the existing Standard. Existing Definition in the Standard: “Approved- Shall mean approved by an entity adopting and requiring the use of this Standard as a result of investigation and tests conducted by the entity or by reason of accepted principles or tests by nationally recognized organizations”
Can you please clarify whether the hot water operational control devices will include both those for sinks as well as those for showers? Or any other types?
I am aware of devices for showers (a well known product is called ShowerStart) and also motion, touch or pedal operated faucets. The intent of such devices is to reduce the waste of water, either while waiting for hot water to arrive a a shower or in the case of the faucet control during the use periods at the sink.
Equation 6 shows the potential for the inclusion of such devices as CDeff (see excerpt below).
oWgpd = refWgpd * oFrac * (1-oCDeff) where oWgpd = daily operational hot water waste quantity oFrac = 0.25 = fraction of hot water waste attributable to standard operating conditions (see above discussion) oCDeff = 0.0 (until specific Hot Water Operational Control Devices have been approved)
As shown, it appears that there can only be one such factor. However, if a faucet has an operational control, it is likely to have both a different factor and will impact a different number of gallons.
CDeff also appears in Equation 9. The same concern applies in both cases.
I think that the method should be flexible enough to account for any approved operational control device.
Reason: This is covered by the provisions of the standard by requiring that such devices be approved, with the meaning of “approved” provided by Section 3 of the existing Standard. Existing Definition in the Standard: “Approved- Shall mean approved by an entity adopting and requiring the use of this Standard as a result of investigation and tests conducted by the entity or by reason of accepted principles or tests by nationally recognized organizations”
Comment #18Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 3Paragraph / Figure / Table / Note: Equation 4.2-12Comment Intent: Not an ObjectionComment Type: TechnicalComment: In Comment 17, the page number and equation references were taken from the Justifcation and Background document. The same questions apply to the equations in the Addenda itself. These include 4.2-12 and 4.1-17 (which appears to be misnumbered) Response: Rejected Reason: This is covered by the provisions of the standard by requiring that such devices be approved, with the meaning of “approved” provided by Section 3 of the existing Standard. Existing Definition in the Standard: “Approved- Shall mean approved by an entity adopting and requiring the use of this Standard as a result of investigation and tests conducted by the entity or by reason of accepted principles or tests by nationally recognized organizations”
In Comment 17, the page number and equation references were taken from the Justifcation and Background document.
The same questions apply to the equations in the Addenda itself. These include 4.2-12 and 4.1-17 (which appears to be misnumbered)
Comment #19Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 5Paragraph / Figure / Table / Note: Equation 4.1-17Comment Intent: Not an ObjectionComment Type: TechnicalComment: Equation 4.1-17 (probably misnumbered) explains pEratio for standard and recirculation systems as excerpted below. pEratio = piping length energy ratio where for standard system: pEratio = PipeL / refpipeL for recirculation systems: pEratio = LoopL / refLoopL The description of the two ratios make sense when both the standard reference and the rated building have either a standard or a recirculation system. However, there is another case, when the rated building has a recirculation system and the reference building has a standard system. in this case, the pEration would appear to be LoopL / refpipeL. For example, in Table 4.2.2.5.2.11(6) Hot water distribution system relative annual energy waste factors the ratio between Recirculation without control or with timer control and standard systems is 467.2/32.0=14.6. When insulated, the ratio is 233.6/28.8=8.1. However, if the standard system is not insulated and circulation system is, the ration is 233.6/32=7.3. Please look at the ratios and the numbers in Table 4.2.2.5.2.11(6) Hot water distribution system relative annual energy waste factors to make sure that the underlying math is correct. The Justification and Background document has the same ratios in Equation 9. Response: Rejected Reason: The reference home always has a standard trunk and branch piping system. The pEratio term is only used to determine the effectiveness of the piping length with respect to the appropriate reference piping length.
Equation 4.1-17 (probably misnumbered) explains pEratio for standard and recirculation systems as excerpted below.
pEratio = piping length energy ratio where for standard system: pEratio = PipeL / refpipeL for recirculation systems: pEratio = LoopL / refLoopL
The description of the two ratios make sense when both the standard reference and the rated building have either a standard or a recirculation system. However, there is another case, when the rated building has a recirculation system and the reference building has a standard system. in this case, the pEration would appear to be LoopL / refpipeL.
For example, in Table 4.2.2.5.2.11(6) Hot water distribution system relative annual energy waste factors the ratio between Recirculation without control or with timer control and standard systems is 467.2/32.0=14.6. When insulated, the ratio is 233.6/28.8=8.1. However, if the standard system is not insulated and circulation system is, the ration is 233.6/32=7.3.
Please look at the ratios and the numbers in Table 4.2.2.5.2.11(6) Hot water distribution system relative annual energy waste factors to make sure that the underlying math is correct.
The Justification and Background document has the same ratios in Equation 9.
Reason: The reference home always has a standard trunk and branch piping system. The pEratio term is only used to determine the effectiveness of the piping length with respect to the appropriate reference piping length.
Comment #20Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 5Paragraph / Figure / Table / Note: Sec. 4.2.2.5.2.11.2 - Eq. 4.2 -17Comment Intent: Not an ObjectionComment Type: EditorialComment: There is a typo in the terms defined for this equation. The variable “oEWfact” is referred to as "bEWfact.” Change "bEWfact " to "oEWfact." Proposed Change: [4.2.2.5.2.12] sEWfact = EWfact – bEWfact oEWfact = structural portion of hot water energy waste Response: Accepted Reason: Editorial correction of typographical error.
There is a typo in the terms defined for this equation. The variable “oEWfact” is referred to as "bEWfact.” Change "bEWfact " to "oEWfact."
[4.2.2.5.2.12] sEWfact = EWfact – bEWfact oEWfact = structural portion of hot water energy waste
Comment #21Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 2Paragraph / Figure / Table / Note: Table 4.2.2.5.2.11(1) Hot water fixture effectivenessComment Intent: Not an ObjectionComment Type: TechnicalComment: The document “Justification and Background BSR/RESNET 301-2014, Addendum A-201x PD-02” simply states that the 0.95 factor for low-flow fixtures, Feff, was derived from data provided by Klein (Roberts 2014), with no additional context. Given that the federal minimum standard for showerheads is 2.5 gpm and the low-flow requirement in the proposed amendment is 2.0 gpm, an Feff factor of 0.80 (i.e., 2.0/2.5) seems more appropriate than 0.95. While bathroom and kitchen faucets will also deliver hot water, the showerheads will constitute a large majority of total fixture hot water consumption. Furthermore, low-flow bathroom sink faucets are often rated at 1.5 gpm or less and, therefore, will likely contribute an even greater percentage of savings relative to the federal minimum standards (i.e., 1.5 / 2.2 gpm = 0.68). Simply based upon the ratio of the performance defined in the standard (2 gpm) relative to federal minimum standards (2.5 gpm) for showerheads, the factor for Eff should be 0.80 rather than 0.95. Proposed Change: [Table 4.2.2.5.2.11(1) Hot water fixture effectiveness] Plumbing Fixture Description Feff Standard-flow: showers ≤2.5 gpm and faucets ≤2.2 gpm 1.00 Low-flow: all showers and faucets ≤2.0 gpm 0.95 0.80 Response: Rejected Reason: Field measurements that are the basis of the 0.95 factor have shown that hot water savings are not directly proportional to the minimum requirements for fixtures. Among the reasons is that standard fixtures are not always turned on to their maximum capacity, while improved fixtures may be.
The document “Justification and Background BSR/RESNET 301-2014, Addendum A-201x PD-02” simply states that the 0.95 factor for low-flow fixtures, Feff, was derived from data provided by Klein (Roberts 2014), with no additional context.
Given that the federal minimum standard for showerheads is 2.5 gpm and the low-flow requirement in the proposed amendment is 2.0 gpm, an Feff factor of 0.80 (i.e., 2.0/2.5) seems more appropriate than 0.95.
While bathroom and kitchen faucets will also deliver hot water, the showerheads will constitute a large majority of total fixture hot water consumption. Furthermore, low-flow bathroom sink faucets are often rated at 1.5 gpm or less and, therefore, will likely contribute an even greater percentage of savings relative to the federal minimum standards (i.e., 1.5 / 2.2 gpm = 0.68).
Simply based upon the ratio of the performance defined in the standard (2 gpm) relative to federal minimum standards (2.5 gpm) for showerheads, the factor for Eff should be 0.80 rather than 0.95.
[Table 4.2.2.5.2.11(1) Hot water fixture effectiveness]
Plumbing Fixture Description Feff Standard-flow: showers ≤2.5 gpm and faucets ≤2.2 gpm 1.00 Low-flow: all showers and faucets ≤2.0 gpm 0.95 0.80
Reason: Field measurements that are the basis of the 0.95 factor have shown that hot water savings are not directly proportional to the minimum requirements for fixtures. Among the reasons is that standard fixtures are not always turned on to their maximum capacity, while improved fixtures may be.
Comment #22Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 5Paragraph / Figure / Table / Note: Eq. 4.2-17Comment Intent: ObjectionComment Type: TechnicalComment: The term "refLoopL" is currently defined as refPipeL * 2.0. By simply doubling refPipeL, the 10 ft that's added per floor and the 5 ft that's added for unconditioned basements will also be doubled. This logic is different than the approach for LoopL, which takes the hot water recirculation loop piping length and adds 10 ft per floor and 5 ft for unconditioned basements. The term "refLoopL" can be more accurately defined and made more consistent with the logic for LoopL. Proposed Change: refLoopL = refPipeL * 2.0 2 * 2 * (CFA / Nfl ) ^ 0.5 + 10 * Nfl + 5 * Bsmt Response: Accept as modified Reason: For multi-story homes 2*10 * number of floors is still the correct calculation for determining the loop pipe length for the upper floors. For single story homes and the first floor of multi-story homes the 2*10 feet needs to be deducted from loop length because it is already included in the branch length. The following modifications (in italics) will be made to the addendum to accomplish this change: BranchL = measured length of the branch hot water piping from the recirculation loop to the farthest hot water fixture from the recirculation loop, measured longitudinally from plans, assuming the branch hot water piping does not run diagonally, plus 10 feet of piping for each floor level, plus 5 feet of piping for unconditioned basements (if any) LoopL = hot water recirculation loop piping length including both supply and return sides of the loop, measured longitudinally from plans, assuming the hot water piping does not run diagonally, plus 10 20 feet of piping for each floor level greater than one plus 5 10 feet of piping for unconditioned basements. refLoopL = 2.0 * refPipeL – 20 refPipeL * 2.0
The term "refLoopL" is currently defined as refPipeL * 2.0. By simply doubling refPipeL, the 10 ft that's added per floor and the 5 ft that's added for unconditioned basements will also be doubled. This logic is different than the approach for LoopL, which takes the hot water recirculation loop piping length and adds 10 ft per floor and 5 ft for unconditioned basements.
The term "refLoopL" can be more accurately defined and made more consistent with the logic for LoopL.
refLoopL = refPipeL * 2.0 2 * 2 * (CFA / Nfl ) ^ 0.5 + 10 * Nfl + 5 * Bsmt
Accept as modified
Reason: For multi-story homes 2*10 * number of floors is still the correct calculation for determining the loop pipe length for the upper floors. For single story homes and the first floor of multi-story homes the 2*10 feet needs to be deducted from loop length because it is already included in the branch length.
The following modifications (in italics) will be made to the addendum to accomplish this change:
BranchL = measured length of the branch hot water piping from the recirculation loop to the farthest hot water fixture from the recirculation loop, measured longitudinally from plans, assuming the branch hot water piping does not run diagonally, plus 10 feet of piping for each floor level, plus 5 feet of piping for unconditioned basements (if any)
LoopL = hot water recirculation loop piping length including both supply and return sides of the loop, measured longitudinally from plans, assuming the hot water piping does not run diagonally, plus 10 20 feet of piping for each floor level greater than one plus 5 10 feet of piping for unconditioned basements.
refLoopL = 2.0 * refPipeL – 20 refPipeL * 2.0
Comment #23Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: AllParagraph / Figure / Table / Note: n/aComment Intent: Not an ObjectionComment Type: GeneralComment: It is simply noted that, in addition to the changes made to the technical calculations, the minimum rated features and verification process for Raters will need to be modified. Several specific areas that will need to be addressed include: determining the location of the farthest fixture in relation to the water heater (i.e. pipe length), the verification of the distribution system type, the verification of the fixture flow efficiency (i.e. gallons per minute rating), and the rated efficiency of any drainwater heat recovery systems used. Response: Accepted Reason: The commenter points out that changes to the standard rater verification procedures used to determine hot water system characteristics will need to be updated when this change becomes effective. No change in the provisions of the proposed addendum are proposed or necessary.
It is simply noted that, in addition to the changes made to the technical calculations, the minimum rated features and verification process for Raters will need to be modified. Several specific areas that will need to be addressed include: determining the location of the farthest fixture in relation to the water heater (i.e. pipe length), the verification of the distribution system type, the verification of the fixture flow efficiency (i.e. gallons per minute rating), and the rated efficiency of any drainwater heat recovery systems used.
Reason: The commenter points out that changes to the standard rater verification procedures used to determine hot water system characteristics will need to be updated when this change becomes effective. No change in the provisions of the proposed addendum are proposed or necessary.
Comment #24Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: Page 1, 3.2, 6 and 4.2..2 (1) Page 4, 4.2.2.5.2.11.1Comment Intent: Not an ObjectionComment Type: GeneralComment: We are main HERS raters in Canada and work with many Ontario builders, both large and small. Drain water heat recovery (DWHR) is used in Ontario by over 400 builders and has been common for many years now. Both builder and home owner satisfaction is extremely high. Water heating is generally the second highest energy load in homes and these units provide builders more HERS points at less cost. This proposal appropriately considers local cold water temperatures, so that energy savings will be lower in Florida than it is in Chicago, for example. By supporting this, Resnet will also be able to help Cresent (Canadian Residential Energy Services Network) which is trying to move forward the HERS Index. In Ontario, HERS is recognized by the OBC (Ontario Building Code) and DWHR is widely used as one of the most cost effective ways to model energy performance upgrades. Response: Accepted Reason: Supportive comment requesting no change in the provisions of the proposed standard.
We are main HERS raters in Canada and work with many Ontario builders, both large and small.
Drain water heat recovery (DWHR) is used in Ontario by over 400 builders and has been common for many years now. Both builder and home owner satisfaction is extremely high. Water heating is generally the second highest energy load in homes and these units provide builders more HERS points at less cost.
This proposal appropriately considers local cold water temperatures, so that energy savings will be lower in Florida than it is in Chicago, for example.
By supporting this, Resnet will also be able to help Cresent (Canadian Residential Energy Services Network) which is trying to move forward the HERS Index. In Ontario, HERS is recognized by the OBC (Ontario Building Code) and DWHR is widely used as one of the most cost effective ways to model energy performance upgrades.
Comment #25Amendment: Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)Page Number: 4Paragraph / Figure / Table / Note: 4.2.2.5.2.11.1 Drain Water Heat Recovery (DWHR) UnitsComment Intent: Not an ObjectionComment Type: TechnicalComment: This response addresses comments submitted about Drain Water Heat Recovery. A) MATURE TECHNOLOGY To date, there are well over 40,000 vertical Drain Water Heat Recovery (DWHR) systems installed across all sectors and building types; most are in homes and multi-family residential. B) FIELD PERFORMANCE AND PREDICTED PERFORMANCE OF VERTICALY INSTALLED DWHR SYSTEMS DWHR units are most commonly installed vertically because the falling film of drain water has a very high heat transfer rate to the inner wall resulting in a high performance for amount of heat exchanger surface area. Also, the falling drain water naturally does not foul up the inner wall so performance does not degrade while keeping these heat exchangers maintenance-free. It is important to note that extensive field research has been completed on vertically installed DWHR systems in homes and multi-family residential buildings by a number of agencies, including LBNL, Natural Resources Canada and various utilities. My company has been involved with this research since 2000. One can confidently predict average energy savings for vertically mounted DWHR units, as a result of this research and labeled third-party ratings of DWHR units according to a strict and very repeatable testing standard (CSA B55.1). Of course, energy savings will vary by actual hot water load and the efficiency of the DWHR unit; this proposed procedure does that accurately. Various other procedures exist for calculation of performance, some use first principles energy balance (as in this submission), others use on-site energy factor (was proposed by the EPA years ago) for the entire water heating system and other methods use percentages (% savings, % energy that hot water comprises). Each of these methods yield similar final results with the same load assumptions and each has their advantages and drawbacks. For the calculation method submitted, energy savings is accurately and appropriately calculated according to an energy balance method and energy saved will be lower in warmer climate zones, assuming all other things are equal. B) CSA STANDARDS These standards are both for vertically installed DWHR units and were developed because this is an established industry. The CSA committee has expressed interest, specifically to a company with horizontal systems, in developing horizontal standards. For clarity the two existing CSA Standards cited have two entirely different purposes: 1) CSA B55.1: is for Safety and Quality 2) CSA B55.2: is for Performance, which includes both Efficiency and Pressure Loss at a fixed, standard flow rate In order to third-party label (e.g. by Intertek) DWHR units according to these standards, strict processes must be followed, including: -quality control tracking and traceability (for both standards) -testing at an independent lab(s) with instrumentation that has up-to-date ISO 17025 calibration (for B55.1) -every unit must be pressure tested to ensure there are no leaks (for B55.2) -regular random factory audits - 4 times per year -Type L (or thicker) copper tube for the potable water-side of the heat exchanger (for B55.2) DWHR units that are primarily designed for vertical installation is a mature industry with safety, quality and performance verification on every single product shipped. These two standards are also the only two standards required in IECC 2015: -B55.2 is mandatory for all DWHR units, -efficiency for credits is according to B55.1 and -maximum mains water pressure loss levels, as measured by B55.1, are are imposed depending upon installation type C) FIELD PERFORMANCE AND PREDICTED PERFORMANCE OF (NEAR) HORIZONTALLY INSTALLED DWHR SYSTEMS It should be noted that: 1) As with any horizontal drain pipe, all horizontally installed DWHR systems will foul, thereby reducing efficiency. The decrease in efficiency over time is unknown. 2) It is not a good idea to require cleaning of DWHR systems, whether installed for grey water or black water. 3) One cannot actually install units exactly horizontal because there needs to be an angle above horizontal in order to maintain the drain water velocity. The angle of orientation from horizontal can have a large impact upon efficiency; at present there is no means for requiring specific angle(s) of installation. There is no independent field performance available of horizontally mounted DWHR systems in homes and/or multi-family residential buildings. However, it is a good idea to have this research done. D) IAPMO 92-2012 AND LIMITATIONS The IAPMO 92-2012 standard is only for Safety and Quality of various heat exchangers and was also not specifically designed for DWHR technology. IAPMO 92-2012 is not, as another commenter seems to have implied, a performance standard. It does not have measurement and third-party labelling for efficiency and/or pressure loss. This standard also allows for the use of thinner walled Type M copper in the fabrication of conforming heat exchangers; Type M copper tube is not permitted for use in some jurisdictions and building types in North America. There is no testing / third-party labelling Performance Standard for horizontally oriented DWHR systems, therefore there is no means for HERS raters and code officials to determine that any specific unit, when installed horizontally, will delivery any energy savings either when installed or in the future, after fouling has reached its limit. When there is field performance research and a third-party Performance Standard for horizontally installed DWHR units, it does make sense to consider including horizontally installed DWHR units in ANSI/RESNET 301-2014. Response: Accepted Reason: The information is duly noted but the commenter does not propose a change to the Addendum.
This response addresses comments submitted about Drain Water Heat Recovery.
A) MATURE TECHNOLOGY To date, there are well over 40,000 vertical Drain Water Heat Recovery (DWHR) systems installed across all sectors and building types; most are in homes and multi-family residential.
B) FIELD PERFORMANCE AND PREDICTED PERFORMANCE OF VERTICALY INSTALLED DWHR SYSTEMS DWHR units are most commonly installed vertically because the falling film of drain water has a very high heat transfer rate to the inner wall resulting in a high performance for amount of heat exchanger surface area. Also, the falling drain water naturally does not foul up the inner wall so performance does not degrade while keeping these heat exchangers maintenance-free.
It is important to note that extensive field research has been completed on vertically installed DWHR systems in homes and multi-family residential buildings by a number of agencies, including LBNL, Natural Resources Canada and various utilities. My company has been involved with this research since 2000. One can confidently predict average energy savings for vertically mounted DWHR units, as a result of this research and labeled third-party ratings of DWHR units according to a strict and very repeatable testing standard (CSA B55.1). Of course, energy savings will vary by actual hot water load and the efficiency of the DWHR unit; this proposed procedure does that accurately. Various other procedures exist for calculation of performance, some use first principles energy balance (as in this submission), others use on-site energy factor (was proposed by the EPA years ago) for the entire water heating system and other methods use percentages (% savings, % energy that hot water comprises). Each of these methods yield similar final results with the same load assumptions and each has their advantages and drawbacks. For the calculation method submitted, energy savings is accurately and appropriately calculated according to an energy balance method and energy saved will be lower in warmer climate zones, assuming all other things are equal.
B) CSA STANDARDS These standards are both for vertically installed DWHR units and were developed because this is an established industry. The CSA committee has expressed interest, specifically to a company with horizontal systems, in developing horizontal standards. For clarity the two existing CSA Standards cited have two entirely different purposes: 1) CSA B55.1: is for Safety and Quality 2) CSA B55.2: is for Performance, which includes both Efficiency and Pressure Loss at a fixed, standard flow rate In order to third-party label (e.g. by Intertek) DWHR units according to these standards, strict processes must be followed, including: -quality control tracking and traceability (for both standards) -testing at an independent lab(s) with instrumentation that has up-to-date ISO 17025 calibration (for B55.1) -every unit must be pressure tested to ensure there are no leaks (for B55.2) -regular random factory audits - 4 times per year -Type L (or thicker) copper tube for the potable water-side of the heat exchanger (for B55.2)
DWHR units that are primarily designed for vertical installation is a mature industry with safety, quality and performance verification on every single product shipped. These two standards are also the only two standards required in IECC 2015: -B55.2 is mandatory for all DWHR units, -efficiency for credits is according to B55.1 and -maximum mains water pressure loss levels, as measured by B55.1, are are imposed depending upon installation type
C) FIELD PERFORMANCE AND PREDICTED PERFORMANCE OF (NEAR) HORIZONTALLY INSTALLED DWHR SYSTEMS It should be noted that: 1) As with any horizontal drain pipe, all horizontally installed DWHR systems will foul, thereby reducing efficiency. The decrease in efficiency over time is unknown. 2) It is not a good idea to require cleaning of DWHR systems, whether installed for grey water or black water. 3) One cannot actually install units exactly horizontal because there needs to be an angle above horizontal in order to maintain the drain water velocity. The angle of orientation from horizontal can have a large impact upon efficiency; at present there is no means for requiring specific angle(s) of installation. There is no independent field performance available of horizontally mounted DWHR systems in homes and/or multi-family residential buildings. However, it is a good idea to have this research done.
D) IAPMO 92-2012 AND LIMITATIONS The IAPMO 92-2012 standard is only for Safety and Quality of various heat exchangers and was also not specifically designed for DWHR technology. IAPMO 92-2012 is not, as another commenter seems to have implied, a performance standard. It does not have measurement and third-party labelling for efficiency and/or pressure loss. This standard also allows for the use of thinner walled Type M copper in the fabrication of conforming heat exchangers; Type M copper tube is not permitted for use in some jurisdictions and building types in North America. There is no testing / third-party labelling Performance Standard for horizontally oriented DWHR systems, therefore there is no means for HERS raters and code officials to determine that any specific unit, when installed horizontally, will delivery any energy savings either when installed or in the future, after fouling has reached its limit. When there is field performance research and a third-party Performance Standard for horizontally installed DWHR units, it does make sense to consider including horizontally installed DWHR units in ANSI/RESNET 301-2014.
Reason: The information is duly noted but the commenter does not propose a change to the Addendum.
Return to Proposed Preliminary Draft Addenda A, (BSR/RESNET 301-2014, Addenda A-201x PD-02)