Receptacle and process loads contribute to heat gains in spaces and directly use energy.
Receptacle Power (except multifamily residential) 


Applicability 
All building projects except multifamily residential 
Definition 
Receptacle power includes computers, monitors, printers, copiers, vending machines, residential size refrigerators, personal space heaters and other equipment loads normally served through conventional electrical receptacles. Small servers are included with receptacle power, but large data centers are generally modeled separately. As a ruleofthumb, if the servers are in a room with a dedicated HVAC system, they should be modeled separately. Receptacle power does not include task lighting, equipment used for HVAC purposes, open or closed refrigeration cases, walkin freezers and refrigerators, elevators, and commercial cooking equipment. These loads should be modeled separately. See Sections 6.4.6, 6.4.7 and 6.4.8 for guidelines and requirements on how to model these process loads. Receptacle power is specified at the space level and is modified by the receptacle schedule. Values in the default receptacle schedules for each hour approach but do not exceed 1.0 (see Appendix C). Receptacle power is generally considered an unregulated load and is treated as a neutral dependent input; no credit has been offered for savings. Identical assumptions are made for both the baseline building and the proposed design. Offering credit for receptacle loads is difficult due to their temporal nature and because information is not always available on what equipment will go into the building at the time the plans are being reviewed. Tenants also have the ability to plug and unplug devices or switch them out for different equipment, adding to the difficulty of assigning credit for promised energy efficiency. COMNET provides a procedure for crediting plug load reductions for building owners and/or managers who are willing to make a longterm commitment to purchase ENERGY STAR equipment. 
Units 
Total power (W) for the space or power density (W/ft²) 
Input Restrictions 
Receptacle loads in the proposed design may be calculated in one of three ways:. The first method is neutral independent, the second method is neutral dependent, and the third method treats equipment that result in receptacle loads as an asset and credit may be taken for power reductions from surveyed devices. The three methods are as follows: 1. The COMNET recommended defaults from Appendix B may be used, in which case the same values are used for the baseline building and there is no credit for reductions in the proposed design. 2. If detailed information is known, the receptacle power can be calculated using Equations 3.4.51 and 3.4.52. In this instance, the energy analyst must be able to estimate the number of personal computers, the number of printers and the number of other equipment in the space, as listed in Table 3.4.51. If detailed information is not available, then Method 1 must be used. With Method 2, “Baseline” power from Table 3.4.51 shall be used for both the baseline building and the proposed design. 3. If detailed information is known and the owner/property manager is willing to make a long term commitment to require ENERGY STAR equipment throughout the building, then Method 3 may be used. Method 3 is the same as Method 2, except that the proposed design may use reduced equipment power for surveyed devices from Table 3.4.51 based on the ‘Length of ENERGY STAR Commitment’. 
Baseline Rules 
With Methods 1 and 2, the receptacle power in the baseline building shall be the same as the proposed design. With Method 3, the ‘Baseline’ equipment values from Table 3.4.51 are used with Equations 6.4.51 and 6.4.52 to determine the equipment power for the baseline building. 
Requirements for Long Term Commitment 
One of the largest hurdles is establishing accountability for receptacle load reductions; savings must be verified and credible. A commitment to future good behavior must be documented appropriately, either in leasing language, within corporate or governmental resolutions, or in tenant manuals to ensure that ENERGY STAR equipment will be used not only initially but also for future replacements. The inability to verify long term commitments is one of the obstacles to offering credits for plug load reductions, since the equipment that makes up receptacle loads is short lived and generally replaced within a 35 year timeframe. 
Equations for Estimating Receptacle Loads (Methods 2 and 3) 
This procedure provides a means for more accurately estimating plug loads (Method 2) and for taking credit for energy reductions when the owner is willing to initially install all ENERGY STAR equipment and make a long term commitment to purchase ENERGY STAR equipment for replacements and additions (Method 3). COMNET Methods 2 and 3 are based on procedures developed by NREL^{1} which estimate receptacle and process power density based on a count of computers, printers and other equipment in the space (surveyed equipment). The procedure is shown in Equations 3.4.51 and 3.4.52. (Equation 3.4.51) $$P=\left ( C_{sd}\cdot PD_{sd}+PD{_{misc}} \right )$$ where P is the estimated power density for the space in W/ft². PD_{sd} is an estimate of receptacle power from personal computers, monitors, servers, printers and other “surveyed devices” determined from Equation (3.4.52). Units are W/ft². PD_{misc} is an estimate from Appendix B of miscellaneous receptacle power for equipment not specifically accounted for in PD_{sd}. This value depends on the occupancy of the space. C_{sd}, is an adjustment coefficient from Appendix B based on the occupancy of the space. This coefficient along with PD_{misc} accounts for equipment that is not included among the “surveyed devices”. C_{sd} scales the equipment power of “surveyed devices”, while PD_{misc} is a constant. d is a diversity factor from Appendix B based on the occupancy of the space. (Equation 3.4.52) $$PD_{sd}=\frac{\begin{bmatrix} where N_{xx} is the number of devices in the proposed design for the “xx” surveyed device in question. See Table 3.4.51 for a list of surveyed devices to be included. P_{xx} is the nominal mean power from Table 3.4.51 for the “xx” surveyed device in question. Area is the area of the space in ft². Credit is limited to equipment listed in Table 3.4.51 where the ENERGY STAR program applies, including PCs, monitors, copiers, laser and inkjet printers, vending machines, and refrigerators. No credit is offered for equipment not listed in Table 3.4.51. 1. Griffith, B, et. al., Methodology for Modeling Building Energy Performance across the Commercial Sector, Technical Report, (NREL/TP55041956, March 2008, Appendix C, Section C.14. Note that elevators and escalators have been removed from the NREL equation, since they are treated separately. 
Table 3.4.51: Nominal Mean Power for Surveyed Devices
Source: See 150928 Plug Loads Calcs TSD.pdf
Subscript 
Description 
Baseline 
Length of ENERGY STAR Commitment 

5 y 
10 y 
15 y 
20 y 
30 y 

PCdt 
Desktop Computer 
65 
58 
52 
47 
43 
37 
PCnb 
Notebook Computer 
25 
22 
20 
18 
17 
15 
Mon 
Monitor 
30 
28 
26 
25 
24 
23 
Svr 
Server 
524 
524 
524 
524 
524 
524 
POS 
Point of Sale Device 
48 
48 
48 
48 
48 
48 
PRNTlas 
Printer Laser 
110 
102 
96 
91 
87 
81 
PRNTink 
Printer Inkjet 
25 
22 
19 
17 
16 
13 
Copy 
Copy Machine 
372 
365 
360 
356 
352 
347 
Fax 
Fax Machine 
55 
51 
47 
44 
42 
39 
Refrig 
Residential Refrigerator 
350 
332 
317 
304 
294 
280 
Vend 
Vending Machine 
400 
363 
333 
308 
288 
259 
Receptacle Power MultiFamily Residential 


Applicability 
Multifamily residential building projects 

Definition 
For multifamily projects, receptacle power includes the refrigerator, cooking equipment, clothes washer, clothes dryer and other major appliances. Receptacle power is specified at the space level and is modified by the receptacle schedule. Values in the default receptacle schedules for each hour approach but do not exceed 1.0 (see Appendix C). Much receptacle power in residences is considered unregulated load and is modeled as a neutral independent input; no credit is offered for savings. Identical assumptions are made for both the baseline building and the proposed design. However for refrigerators and clothes washers, the modeling assumptions for the proposed building can differ from the baseline building when ENERGY STAR complying equipment is used in the proposed design. 

Units 
Total power (W) for the space or power density (W/ft²) 

Input Restrictions 
Receptacle loads in the proposed design shall be calculated on the basis of: the number of dwelling units, the number of bedrooms, the floor area, and the use of ENERGY STAR appliances. Credit for ENERGY STAR appliances applies only to refrigerators and clothes washers. Other equipment energy use is neutral independent. Lobbies, corridors and other common spaces shall determine plug and process electrical loads using the general procedure for nonresidential buildings. 

Baseline Rules 
The receptacle power in the baseline building shall be determined using the same method (see below) as the proposed design, but conventional equipment shall be assumed for the refrigerator and clothes washer. 

Procedure for Estimating Receptacle Power 
Receptacle loads in the proposed design may be calculated in one of two ways:1. The first simplified method may be used when each dwelling unit has its own clothes washer and dryer and all of the dwelling units use either electricity or gas for cooking and clothes drying. The second method is more flexible and must be used when some dwelling units have inunit washers and dryers and some do not, or when some of the dwelling units use gas while others use electricity. The two methods are as follows: Method OneThe annual electric energy for dwelling units in the multifamily building is given by equation 3.4.53 below: (Equation 3.4.53) $$ kWh_{total} = NmbrDU \cdot a + NmbrBR \cdot b + FlrArea \cdot c $$ where kWh_{total} the total annual electrical receptacle energy for the multifamily building (kWh/y) NmbrDU number of dwelling units in the multifamily building NmbrBR number of bedrooms in the multifamily building (efficiency apartments count as one) FlrArea finished floor area for all dwelling units. a, b, and c coefficients taken from Table 3.4.52 Table 3.4.52: Annual Residential Energy Use  Method OneNote: Use values in parenthesis when all the dwelling units have ENERGY STAR refrigerators and clothes washers.
Once kWh_{total} is determined, it is converted to power by dividing by the number of fulltime equivalent hours used in the receptacle schedule and by adjusting units. This step is shown in equation 3.4.54. . (Equation 3.4.54) $$Power (W/ft2) = \frac{kWh_{total} \cdot 1,000}{FTEhours}$$ where FTEhours fulltime equivalent hours used in the receptacle schedule. The default value from Appendix C is 5,840 hours (hours) Method TwoMethod Two can be used under any conditions, but is required when some or all of the clothes washers and/or dryers are located in common areas or when some of the dwelling units have gas for cooking and or drying clothes while other units use electricity. The annual electricity use is given in equations 3.4.55 through 3.4.510: (Equation 3.4.55) $$kWh_{total}=kWh_{ref}+kWh_{cths}+kWh_{cook}+kWh_{dry}+kWh_{misc}$$ (Equation 3.4.56) $$kWh_{ref} = NmbrDU_{E*} \cdot 423 + NmbrDU_{conv} \cdot 529$$ (Equation 3.4.57) $$\begin{align} kWh_{du,cths} = & NmbrCW_{du,E*} \cdot 57 + NmbrCW_{du,conv} \cdot 81 + \\ & NmbrCW_{com,E*} \cdot 138 + NmbrCW_{com,conv} \cdot 196 \end{align} $$ (Equation 3.4.58) $$kWh_{cook} = NmbrDU_{EC} \cdot 604$$ (Equation 3.4.59) $$\begin{align} kWh_{dry} = & NmbrDry_{du,elec} \cdot 418 + NmbrBR_{du,elec} \cdot 139 + \\ & NmbrDry_{com,elec} \cdot 1013 + NmbrBR_{com,elec} \cdot 337 + \\ & NmbrDry_{du,gas} \cdot 38 + NmbrBR_{du,gas} \cdot 12.7+ \\ & NmbrDry_{com,gas} \cdot 92.1 + NmbrBR_{com,gas} \cdot 30.8 \end{align}$$ (Equation 3.4.510) $$kWh_{misc} = FlrArea \cdot 1.05$$ where kWh_{total} the total annual electrical receptacle energy for the multifamily building (kWh/y) kWh_{ref} the annual refrigerator energy for the multifamily building (kWh/y) kWh_{cths} the annual clothes washer energy for the multifamily building (kWh/y) kWh_{cook} the annual cooking energy for the multifamily building (kWh/y) kWh_{dry} the annual clothes dryer energy for the multifamily building (kWh/y) kWh_{misc} the annual miscellaneous energy for the multifamily building (kWh/y) NmbrDU_{E*} number of dwelling units with ENERGY STAR refrigerator NmbrDU_{conv} number of dwelling units with conventional refrigerator NmbrCW_{du,E*} number of ENERGY STAR clothes washers located in dwelling units NmbrCW_{com,E*} number of ENERGY STAR clothes washers located in common areas NmbrCW_{du,conv} number of conventional clothes washers located in dwelling units NmbrCW_{com,conv} number of conventional clothes washers located in common areas NmbrDU_{EC} number of dwelling units with electric cooking NmbrDry_{du,elec} number of electric clothes dryers in dwelling units NmbrDry_{com,elec} number of electric clothes dryers in common areas NmbrDry_{du,gas} number of gas clothes dryers in dwelling units NmbrDry_{du,gas} number of gas dryers in common areas NmbrBR_{du,elec} number of bedrooms served by electric clothes dryers in dwelling units NmbrBR_{com,elec} number of bedrooms served by electric clothes dryers in common areas NmbrBR_{du,gas} number of bedrooms served by gas clothes dryers in dwelling units NmbrBR_{com,gas} number of bedrooms served by gas clothes dryers in common areas FlrArea finished floor area for all dwelling units. Once kWh_{total} is calculated, it is converted to power by dividing by the fulltime equivalent (FTE) hours in the schedule of operation and adjusting the units. See equation 3.4.54. 
Table 3.4.53: Annual Residential Energy Use
Annual Energy Use 
Load Fraction 

Per Unit 
Per BR 
Per Area 
Sensible 
Latent 

Electricity in Dwelling Unit (kWh/y) 

Refrigerator^{a} 
529 (423) 
0 
0 
1.00 
0.00 
Clothes washer^{a} 
81 (57) 
0 
0 
0.60 
0.15 
Cooking 
604 
0 
0 
0.40 
0.30 
Clothes dryer (electric) 
418 
139 
0 
0.15 
0.05 
Clothes dryer (gas) 
38.0 
12.7 
0 
1.00 
0.00 
Miscellaneous 
0 
0 
1.05 
0.90 
0.10 
Electricity in Common Space Laundry (kWh/y) 

Clothes washer 
196 (138) 
0 
0 
0.60 
0.15 
Clothes dryer (electric) 
1013 
337 
0 
0.15 
0.05 
Clothes dryer (gas) 
92.1 
30.8 
0 
1.00 
0.00 
Gas in Dwelling Unit (therms/y)^{b} 

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)^{b} 




Clothes dryer 
64.2 
21.3 
0 
0.10 
0.05 
a. Values in parenthesis are to be used for ENERGY STAR equipment in the proposed design
b. Gas in residential dwelling units is addressed in section 3.4.8.
Receptacle Schedule 


Applicability 
All projects 
Definition 
Schedule for receptacle power loads used to adjust the intensity on an hourly basis to reflect timedependent patterns of usage. 
Units 
Data structure: schedule, fraction 
Input Restrictions 
The default schedule is taken from Tables 1 through 11 of Appendix C. 
Baseline Rules 
Schedules for the baseline building shall be identical to the proposed design. 
 1. Both methods are developed from information contained in the ENERGY STAR MultiFamily Highrise Simulation Guidelines, Version 1.0, Revision 03, January 2015, pages 2335.