Commercial gas equipment includes the following:
- Ovens
- Fryers
- Grills
- Other equipment
The majority of gas equipment is located in the space and may contribute both sensible and latent heat. Gas equipment is typically modeled by specifying the rate of peak gas consumption and modifying this with a fractional schedule. Energy consumption data for gas equipment is only beginning to emerge.
Because of these limits, the COMNET procedure for commercial gas is limited. The procedure consists of prescribed power and energy values for use with both the proposed design and the baseline building. No credit for commercial gas energy efficiency features is offered.
The prescribed values are provided in Appendix B.1 Schedules are defaulted to be continuous operation.
|
Gas Equipment Power |
|
|---|---|
|
Applicability |
All buildings that have gas appliances or commercial gas equipment |
|
Definition |
Commercial gas power is the average power for all commercial gas equipment, assuming constant year-round operation. |
|
Units |
Btu/h-ft² |
|
Input Restrictions (except residential) |
The values in Appendix B are prescribed. |
| Input Restrictions (residential) |
Annual gas use for cooking and clothes drying, shall be calculated as shown below: (Equation 3.4.8-1) $$\begin{align} Therms = & NmbrDU_{du,cook} \cdot 45 + \\ & NmbrDU_{du,dry} \cdot 26.5 + NmbrBR_{du,dry} \cdot 8.8 + \\ & NmbrComDry \cdot 64.2 + NmbrBR_{com,dry} \cdot 21.3 \end{align}$$ where Therms annual gas use (therms/y) NmbrDUdu,cook number of dwelling units with gas cooking NmbrDUdu,dry number of dwelling units with in-unit gas clothes drying NmbrBRdu,dry number of bedrooms in dwelling units units with in-unit gas clothes drying NmbrComDry number of dryers in common areas (serving multiple dwelling units) NmbrBRcom,dry number of bedrooms served by common dryers (serving multiple dwelling units) Once the annual therms are determined using equation 3.4.8-1, the annual energy is converted to power by dividing by the full-time equivalent hours of operation in the residential schedule. If the power is to be expressed per floor area, then another adjustment to the value is required. (Equation 3.4.8-2) $$ GasPower = \frac{Therms}{100 \cdot FTEhours} $$ where GasPower rate of gas use in kBtu/h FTEhours full -time equivalent hours in the schedule for gas use. If the residential receptacle schedule is used, the FTE hours are 5,840 100 conversion factor to change therms to kBtu |
|
Baseline Rules |
Same as the proposed design |
Table 3.4.8-1: Annual Residential Gas Use for Cooking and Clothes Drying
Source: Energy Star Multi-Family Highrise Simulation Guidelines, Version 1.0, Revision 03, January 2015, pages 23-35.
|
Annual Energy Use |
Load Fraction |
||||
|
Per Unit |
Per BR |
Per Area |
Sensible |
Latent |
|
|
Gas in Dwelling Unit (therms/y) |
|||||
|
Cooking |
45 |
0 |
0 |
0.40 |
0.30 |
|
Clothes dryer |
26.5 |
8.8 |
0 |
0.10 |
0.05 |
|
Gas in Common Laundry Space (therms/y) |
|
|
|
||
|
Clothes dryer |
64.2 |
21.3 |
0 |
0.10 |
0.05 |
.
|
Gas Equipment Schedule |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The schedule of operation for commercial gas equipment. This is used to convert gas power to energy use. |
|
Units |
Data structure: schedule, fractional |
|
Input Restrictions |
Continuous operation is prescribed. The default values for power are based on continuous operation, although this is not realistic. |
|
Baseline Rules |
Same as the proposed design |
|
Gas Equipment Location |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The assumed location of the gas equipment for modeling purposes. Choices are in the space or external. |
|
Units |
List (see above) |
|
Input Restrictions |
As designed. |
|
Baseline Rules |
Same as the proposed design |
|
Radiation Factor |
|
|---|---|
|
Applicability |
Gas appliances located in the space |
|
Definition |
The fraction of heat gain to appliance energy use |
|
Units |
Fraction |
|
Input Restrictions |
Default value is 0.15. Other values can be used when a detailed inventory of equipment is known. The override value shall be based on data in Table 5C, Chapter 18, ASHRAE HOF, 2009, or similar tested information from the manufacturer. |
|
Baseline Rules |
Same as the proposed design |
- 1See Table C-43, p. 146 of NREL/TP-550-41956, Methodology for Modeling Building Energy Performance across the Commercial Sector, Technical Report, Appendix C, March 2008. The values in this report were taken from Table 8-3 of the California Commercial End-Use Survey, Consultants Report, March 2006, CEC-400-2006-005
Commercial gas equipment includes the following:
· Ovens
· Fryers
· Grills
· Other equipment
The majority of gas equipment is located in the space, but is often placed under an exhaust hood, and may contribute both sensible and latent heat. Gas equipment is typically modeled by specifying the rate of peak gas consumption and modifying this with a fractional schedule. Energy consumption data for gas equipment is only beginning to emerge.
Because of these limits, the procedure for commercial gas is limited. The procedure consists of default values for power density for both the proposed design and the baseline building. These defaults can be overridden if actual values are known. No credit for commercial gas energy efficiency features is offered.
COMNET Appendix B (COMNET 2017) specifies default values that can be used for process and gas loads. Schedules are specified in COMNET Appendix C (COMNET 2017) that reflect diversity in equipment operation. Process and gas loads can also be specified through an input for peak equipment power and associated diversity schedule.
| Gas Equipment and Power Density | |
|---|---|
| Applicability | All buildings that have commercial gas equipment |
| Definition |
Commercial gas power density is the peak power for commercial gas equipment, with operation schedules defined through a separate descriptor. The gas equipment energy use can also be defined through an input of peak gas equipment power with operation schedules defined through a separate descriptor. |
| Units | Btu/h or Btu/h-ft² |
| Input Restrictions | As designed. For cases where design values are not available, defaults specified in COMNET Appendix B (COMNET 2017) may be used. |
| Baseline Building |
Same as the proposed design. However, when quantifying performance that exceeds the requirements of Standard 90.1 (but not when using the Performance Rating as an alternative path for minimum standard compliance ), variations of the power requirements, schedules, or control sequences of the gas equipment modeled in the baseline building from those in the proposed design shall be allowed by the rating authority based upon documentation that the gas equipment installed in the proposed design represents a significant verifiable departure from documented conventional practice. The burden of this documentation is to demonstrate that accepted conventional practice would result in baseline building gas equipment different from that installed in the proposed design. Occupancy and occupancy schedules shall not be changed. NOTE: Any variation between proposed and baseline gas equipment power should be flagged for rating authority approval and inspection. |
| Gas Equipment and Heat Gain Functions | |
|---|---|
| Applicability | All projects |
| Definition |
The fuel input to the gas equipment ultimately appears as heat that contributes to zone loads. This heat can be divided into four different fractions. These are given by the input fields. · Fraction Latent: This field is a decimal number between 0.0 and 1.0 and is used to characterize the amount of latent heat given off by the gas equipment in a zone. The number specified in this field will be multiplied by the total energy consumed by gas equipment to give the amount of latent energy produced by the gas equipment. This energy affects the moisture balance within the zone. · Fraction Radiant: This field is a decimal number between 0.0 and 1.0 and is used to characterize the amount of long-wave radiant heat being given off by gas equipment in a zone. The number specified in this field will be multiplied by the total energy consumed by gas equipment to give the amount of long wavelength radiation gain from electric equipment in a zone. · Fraction Lost: This field is a decimal number between 0.0 and 1.0 and is used to characterize the amount of “lost” heat being given off by gas equipment in a zone. The number specified in this field will be multiplied by the total energy consumed by gas equipment to give the amount of heat that is “lost” and does not impact the zone energy balances. This might correspond to gas energy converted to mechanical work or heat that is vented to the atmosphere. · Fraction Convected: This field is a decimal number between 0.0 and 1.0 and is used to characterize the fraction of the heat from gas equipment convected to the zone air. The sum of all 4 of these fractions should be 1. |
| Units | Data structure: fraction |
| Input Restrictions |
As designed. If not specified by the user, default values for gas equipment heat gain fractions will be used. For software that specifies the fraction of the heat gain that is lost from the space, this fraction shall be defaulted to 0.70. The default values for fraction radiant, fraction latent, and fraction convected will be specified as 0.15, 0.05, and 0.10 respectively. |
| Baseline Building |
Same as proposed |
| Gas Equipment Schedule | |
|---|---|
| Applicability | All buildings that have commercial gas equipment |
| Definition |
The schedule of operation for commercial gas equipment. This is used to convert gas power to energy use. |
| Units | Data structure: schedule, fractional |
| Input Restrictions |
As determined by building owner or design professional |
| Baseline Building |
Same as the proposed design |
| Gas Equipment Location | |
|---|---|
| Applicability | All buildings that have commercial gas equipment |
| Definition |
The assumed location of the gas equipment for modeling purposes. Choices are in the space or external. |
| Units | List (see above) |
| Input Restrictions |
As designed |
| Baseline Building |
Same as the proposed design |
Commercial gas equipment includes the following:
- Ovens
- Fryers
- Grills
- Other equipment
The majority of gas equipment is located in the space and may contribute both sensible and latent heat. Gas equipment is typically modeled by specifying the rate of peak gas consumption and modifying this with a fractional schedule. Energy consumption data for gas equipment is only beginning to emerge.
Because of these limits, the COMNET procedure for commercial gas is limited. The procedure consists of prescribed power and energy values for use with both the proposed design and the baseline building. No credit for commercial gas energy efficiency features is offered.
The prescribed values are provided in Appendix B.1 Schedules are defaulted to be continuous operation.
|
Gas Equipment Power |
|
|---|---|
|
Applicability |
All buildings that have gas appliances or commercial gas equipment |
|
Definition |
Commercial gas power is the average power for all commercial gas equipment, assuming constant year-round operation. |
|
Units |
Btu/h-ft² |
|
Input Restrictions (except residential) |
The values in Appendix B are prescribed. |
| Input Restrictions (residential) |
Annual gas use for cooking and clothes drying, shall be calculated as shown below: (Equation 3.4.8-1) $$\begin{align} Therms = & NmbrDU_{du,cook} \cdot 45 + \\ & NmbrDU_{du,dry} \cdot 26.5 + NmbrBR_{du,dry} \cdot 8.8 + \\ & NmbrComDry \cdot 64.2 + NmbrBR_{com,dry} \cdot 21.3 \end{align}$$ where Therms annual gas use (therms/y) NmbrDUdu,cook number of dwelling units with gas cooking NmbrDUdu,dry number of dwelling units with in-unit gas clothes drying NmbrBRdu,dry number of bedrooms in dwelling units units with in-unit gas clothes drying NmbrComDry number of dryers in common areas (serving multiple dwelling units) NmbrBRcom,dry number of bedrooms served by common dryers (serving multiple dwelling units) Once the annual therms are determined using equation 3.4.8-1, the annual energy is converted to power by dividing by the full-time equivalent hours of operation in the residential schedule. If the power is to be expressed per floor area, then another adjustment to the value is required. (Equation 3.4.8-2) $$ GasPower = \frac{Therms}{100 \cdot FTEhours} $$ where GasPower rate of gas use in kBtu/h FTEhours full -time equivalent hours in the schedule for gas use. If the residential receptacle schedule is used, the FTE hours are 5,840 100 conversion factor to change therms to kBtu |
|
Baseline Rules |
There is no baseline building. |
Table 3.4.8-1: Annual Residential Gas Use for Cooking and Clothes Drying
Source: Energy Star Multi-Family Highrise Simulation Guidelines, Version 1.0, Revision 03, January 2015, pages 23-35.
|
Annual Energy Use |
Load Fraction |
||||
|
Per Unit |
Per BR |
Per Area |
Sensible |
Latent |
|
|
Gas in Dwelling Unit (therms/y) |
|||||
|
Cooking |
45 |
0 |
0 |
0.40 |
0.30 |
|
Clothes dryer |
26.5 |
8.8 |
0 |
0.10 |
0.05 |
|
Gas in Common Laundry Space (therms/y) |
|
|
|
||
|
Clothes dryer |
64.2 |
21.3 |
0 |
0.10 |
0.05 |
.
|
Gas Equipment Schedule |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The schedule of operation for commercial gas equipment. This is used to convert gas power to energy use. |
|
Units |
Data structure: schedule, fractional |
|
Input Restrictions |
Continuous operation is prescribed. The default values for power are based on continuous operation, although this is not realistic. |
|
Baseline Rules |
There is no baseline building. |
|
Gas Equipment Location |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The assumed location of the gas equipment for modeling purposes. Choices are in the space or external. |
|
Units |
List (see above) |
|
Input Restrictions |
As designed. |
|
Baseline Rules |
There is no baseline building. |
|
Radiation Factor |
|
|---|---|
|
Applicability |
Gas appliances located in the space |
|
Definition |
The fraction of heat gain to appliance energy use |
|
Units |
Fraction |
|
Input Restrictions |
Default value is 0.15. Other values can be used when a detailed inventory of equipment is known. The override value shall be based on data in Table 5C, Chapter 18, ASHRAE HOF, 2009, or similar tested information from the manufacturer. |
|
Baseline Rules |
There is no baseline building. |
- 1See Table C-43, p. 146 of NREL/TP-550-41956, Methodology for Modeling Building Energy Performance across the Commercial Sector, Technical Report, Appendix C, March 2008. The values in this report were taken from Table 8-3 of the California Commercial End-Use Survey, Consultants Report, March 2006, CEC-400-2006-005
Commercial gas equipment includes the following:
- Ovens
- Fryers
- Grills
- Other equipment
The majority of gas equipment is located in the space and may contribute both sensible and latent heat. Gas equipment is typically modeled by specifying the rate of peak gas consumption and modifying this with a fractional schedule. Energy consumption data for gas equipment is only beginning to emerge.
Because of these limits, the COMNET procedure for commercial gas is limited. The procedure consists of prescribed power and energy values for use with both the proposed design and the baseline building. No credit for commercial gas energy efficiency features is offered.
The prescribed values are provided in Appendix B.1 Schedules are defaulted to be continuous operation.
|
Gas Equipment Power |
|
|---|---|
|
Applicability |
All buildings that have gas appliances or commercial gas equipment |
|
Definition |
Commercial gas power is the average power for all commercial gas equipment, assuming constant year-round operation. |
|
Units |
Btu/h-ft² |
|
Input Restrictions (except residential) |
The values in Appendix B are prescribed. |
| Input Restrictions (residential) |
Annual gas use for cooking and clothes drying, shall be calculated as shown below: (Equation 3.4.8-1) $$\begin{align} Therms = & NmbrDU_{du,cook} \cdot 45 + \\ & NmbrDU_{du,dry} \cdot 26.5 + NmbrBR_{du,dry} \cdot 8.8 + \\ & NmbrComDry \cdot 64.2 + NmbrBR_{com,dry} \cdot 21.3 \end{align}$$ where Therms annual gas use (therms/y) NmbrDUdu,cook number of dwelling units with gas cooking NmbrDUdu,dry number of dwelling units with in-unit gas clothes drying NmbrBRdu,dry number of bedrooms in dwelling units units with in-unit gas clothes drying NmbrComDry number of dryers in common areas (serving multiple dwelling units) NmbrBRcom,dry number of bedrooms served by common dryers (serving multiple dwelling units) Once the annual therms are determined using equation 3.4.8-1, the annual energy is converted to power by dividing by the full-time equivalent hours of operation in the residential schedule. If the power is to be expressed per floor area, then another adjustment to the value is required. (Equation 3.4.8-2) $$ GasPower = \frac{Therms}{100 \cdot FTEhours} $$ where GasPower rate of gas use in kBtu/h FTEhours full -time equivalent hours in the schedule for gas use. If the residential receptacle schedule is used, the FTE hours are 5,840 100 conversion factor to change therms to kBtu |
|
Baseline Rules |
There is no baseline building. |
Table 3.4.8-1: Annual Residential Gas Use for Cooking and Clothes Drying
Source: Energy Star Multi-Family Highrise Simulation Guidelines, Version 1.0, Revision 03, January 2015, pages 23-35.
|
Annual Energy Use |
Load Fraction |
||||
|
Per Unit |
Per BR |
Per Area |
Sensible |
Latent |
|
|
Gas in Dwelling Unit (therms/y) |
|||||
|
Cooking |
45 |
0 |
0 |
0.40 |
0.30 |
|
Clothes dryer |
26.5 |
8.8 |
0 |
0.10 |
0.05 |
|
Gas in Common Laundry Space (therms/y) |
|
|
|
||
|
Clothes dryer |
64.2 |
21.3 |
0 |
0.10 |
0.05 |
.
|
Gas Equipment Schedule |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The schedule of operation for commercial gas equipment. This is used to convert gas power to energy use. |
|
Units |
Data structure: schedule, fractional |
|
Input Restrictions |
Continuous operation is prescribed. The default values for power are based on continuous operation, although this is not realistic. |
|
Baseline Rules |
There is no baseline building. |
|
Gas Equipment Location |
|
|---|---|
|
Applicability |
All buildings that have commercial gas equipment |
|
Definition |
The assumed location of the gas equipment for modeling purposes. Choices are in the space or external. |
|
Units |
List (see above) |
|
Input Restrictions |
As designed. |
|
Baseline Rules |
There is no baseline building. |
|
Radiation Factor |
|
|---|---|
|
Applicability |
Gas appliances located in the space |
|
Definition |
The fraction of heat gain to appliance energy use |
|
Units |
Fraction |
|
Input Restrictions |
Default value is 0.15. Other values can be used when a detailed inventory of equipment is known. The override value shall be based on data in Table 5C, Chapter 18, ASHRAE HOF, 2009, or similar tested information from the manufacturer. |
|
Baseline Rules |
There is no baseline building. |
- 1See Table C-43, p. 146 of NREL/TP-550-41956, Methodology for Modeling Building Energy Performance across the Commercial Sector, Technical Report, Appendix C, March 2008. The values in this report were taken from Table 8-3 of the California Commercial End-Use Survey, Consultants Report, March 2006, CEC-400-2006-005