Conditioning Equipment

Modified on Wed, 20 Sep 2023 at 03:32 PM

Conditioning Equipment

Mechanical Equipment is used for cooling, heating, and/or water heating. The following inputs are common to all mechanical equipment:

Equipment Type	A specific designation describing what kind of equipment is represented by this component type. Different equipment types have different sets of available fuel type(s), distribution type(s), and conditioning type(s). Any equipment not in the list may be modeled using the Custom equipment type. Evaporative coolers should be modeled as air conditioners. If the labeled efficiency is not available, RESNET has specified that a default value of 30 EER should be used (ANSI/RESNET 301-2014). Please reference this article when modeling a Dual Fuel Heat Pump. Please reference this article when modeling a Chiller or Cooling Tower with a Water Loop Heat Pump. Please reference this article when modeling a Shared Boiler with a Water Loop Heat Pump.
Fuel Type	The type of fuel used by this component type. Available options will vary depending on equipment type.
Distribution Type	The method that this component type uses to distribute air, water or another working fluid. Available options will vary depending on equipment type. Note: Forced Air Hydronic systems should be modeled using the Forced Air option.
Conditioning Type (unlabeled field)	This unlabeled field, represented by a number of checkboxes, specifies the type of conditioning (Heating, Cooling and/or Hot Water) that this equipment can provide. Available options will vary depending on equipment type. The selection here will affect which inputs are available.

Common Inputs

The following inputs are available only for equipment that serves that conditioning type

Heating

Efficiency Type (unlabeled field)	This unlabeled field, represented by a dropdown menu, specifies the efficiency measurement of the Heating equipment. Options include: AFUE - Annual Fuel Utilization Efficiency is a standardized measurement of heating system efficiency based on the ratio between annual energy input and output. HSPF - Heating Seasonal Performance Factor is a standardized measure of heat pump efficiency, based on the total heating output of a heat pump, in Btu, divided by the total electric energy input, in watt-hours, under test conditions specified by the Air Conditioning and Refrigeration Institute (AHRI) Standard 210/240. If you are modeling a Dual Fuel Heat Pump, please reference this guide. Please note that Ekotrope will include backup resistance heat and reduced performance in cold weather automatically. In Versions prior to 4.0, this is accomplished by de-rating the HSPF based on the climate conditions according to this article. In Version 4.0 or later, Ekotrope models the performance of the heat pump at each hour based on standard performance curves from NREL, including backup heat as necessary to satisfy the required heating load. If the system is not rated for HSPF, COP @ 47F can be used along with this table to determine HSPF. HSPF2 - Heating Seasonal Performance Factor 2 is the new standardized measure of heat pump efficiency under new test conditions specified by AHRI 210/240 (2020), which will be in effect by January 1, 2023. Ekotrope currently supports HSPF2 for air source heat pumps using the conversion factors specified in ANSI/RESNET 301, reproduced for convenience here. For more information on how HSPF2 differs from HSPF, please visit our blog post on "The Impacts of SEER2 and HSPF2." COP - Coefficient of Performance is the ratio of the rate of heat delivered to the energy input, in consistent units, for a complete heat pump system as-installed over the course of an entire heating season in a given location. This should ONLY be used if the modeler has adequate data or evidence to determine an accurate seasonal, as-installed COP. This value must include backup resistance heat, if applicable. A COP tested in a laboratory at certain rated conditions, e.g. 47F, should NOT be used, nor should a straight "conversion" of HSPF to COP by dividing by 3.413. Adjusted Efficiency - Average annual efficiency, used for equipment not covered by the other three efficiencies. Guidance for Efficiency Types that aren't included: Thermal Efficiency (Et) - some large boilers will be rated in Et rather than AFUE. In this case we recommend converting to AFUE using the following conversion (the resulting number will typically be between 78 & 97): AFUE = (Et% - 10.5%) / 0.875
Efficiency	Enter the seasonal heating efficiency in the units specified by Efficiency Type as measured using Department of Energy (DOE) standard methods. When possible, look up the rated efficiency value in the American Heating and Refrigeration Institute (AHRI) Directory of Certified Product Performance, found at ahrinet.org. Age-based defaults for existing homes are available from ANSI/RESNET 301 Table 4.4.2(3).
Capacity	Output capacity of this equipment in [kBtu/h]. For air source heat pumps, please use the compressor capacity at 47F. For a boiler that is shared with multiple units, use the nominal capacity of the terminal distribution equipment connected to the boiler loop within the dwelling unit (fan coil, terminal heat pump, radiator/convectors, etc).
EAE (Furnace/Boilers only)	The average annual auxiliary electricity consumption measured in kWh. This value is meant to quantify auxiliary electricity consumption of fuel-burning equipment types. This information is reported in the AHRI Consumer’s Directory of Certified Efficiency Ratings. The checkbox “Use Default EAE” will set EAE to a default value as specified by the RESNET Standards. Notes: Starting with Algorithm Version 4.0.0, EAE is no longer used for Furnace calculations. Instead the Measured Fan Watts will be used as entered in the HVAC Grading section. If a measured value is not entered a default of 0.58 W/CFM will be used. This field will not be visible for Shared Boilers. Please enter the correct pump and fan power with the number of units served by the system.

Cooling

Efficiency Type	This unlabeled field, represented by a dropdown menu, specifies the efficiency measurement of the Cooling equipment. Options include: SEER- Seasonal Energy Efficiency Ratio is a standardized measure of air conditioner efficiency based on the total cooling output of an air conditioner in Btu/h divided by the total electric energy input, in watt-hours, under test conditions specified by the Air Conditioning and Refrigeration Institute (AHRI) Standard 210/240. SEER2 - Seasonal Energy Efficiency Ratio 2 is the new standardized measure of air conditioner efficiency under new test conditions specified by AHRI 210/240 (2020), which will be in effect by January 1, 2023. Ekotrope currently supports SEER2 for air source heat pumps and air conditioners using the conversion factors specified in ANSI/RESNET 301, reproduced for convenience here. For more information on how SEER2 differs from SEER, please visit our blog post on "The Impacts of SEER2 and HSPF2." EER - Energy Efficiency Ratio is the ratio of net equipment cooling capacity in Btu/h to total rate of electric input in watts under designated operating conditions.
Efficiency	Enter the seasonal cooling efficiency as measured using Department of Energy (DOE) standard methods. When possible, look up the rated efficiency value in the American Heating and Refrigeration Institute (AHRI) Directory of Certified Product Performance. Age-based defaults for existing homes are available from ANSI/RESNET 301 Table 4.4.2(3). Note: To model a Chiller system in Ekotrope, the SEER efficiency of the system must be calculated using the equation explained in this article.
Capacity	Output capacity of this equipment in [kBtu/h]. For a cooling system that is shared with multiple units, use the nominal capacity of the terminal distribution equipment (fan coil, terminal heat pump, etc).

Hot Water

Energy Factor (EF) or Uniform Energy Factor (UEF)	This information should be available in the product documentation or in the AHRI directory. If you are modeling a commercial unit you must use EF. If you need help generating an EF, please see this help article. For indirect (AKA combo, side arm tank) water heaters, we recommend entering the AFUE of the boiler divided by 100 and multiplying by a factor between 0.8 and 0.85 depending on tank size and insulation. Conservatively, we advise using 0.8 but for a low volume (<= 30 gallons) or super insulated (>= R-20) tank, use 0.85.
Tankless?	This box should be checked for tankless or instantaneous water heaters.
Tank Capacity	Enter the DOE rated size of the tank in gallons (for applicable water heater types). If you are rating a home with multiple water heaters, model them each separately. Do not combine them into 1 water heater with a really large tank.
Solar Hot Water System Type	Select the type of solar hot water system. For reference: Dept of Energy on Solar Water Heaters.
% Generation from Solar	The estimated percentage of annual hot water load provided by solar hot water systems. If you have an estimate of the % Generation from Solar from previous projects or from an experienced solar DHW system designer, this estimate should suffice. Alternatively, you can estimate % Generation from Solar by using NREL's System Advisor Model (SAM) to model the solar hot water system. Once the model is completed in SAM, use the ratio Annual Energy Saved/Aux Without Solar as the % Generation here. This is probably the most precise method without data from previous projects.

If Detailed Inputs are enabled for hot water then the following fields will also be available. It is not recommended to use Detailed Inputs for tankless or heat pump water heaters.

Input [kBtu/hr]	Input power of the water heater in kBtu/hr. The AHRI directory uses the unit MBtuh which is equivalent to kBtu/hr (both are thousands of BTU per hour). Electric water heaters are usually rated in kW (AHRI directory shows kWh). To convert kW to kBtu/hr, please multiply by 3.413.
Recovery Efficiency	Describes how efficiently energy is transferred to the water. Recovery Efficiency will be greater than or equal to the Energy Factor. For indirect (side arm tank) water heaters, enter the AFUE of the boiler divided by 100 here.

Equipment Specific Inputs

The following inputs are only available for equipment with the given characteristic:

Backup Heating (for Air Source Heat Pumps)

Backup Fuel Type	For standard heat pumps, choose Electric. For dual fuel heat pumps, choose the secondary fuel (typically natural gas or propane). Any load that cannot be met by the backup system will be assumed to be met by resistance heat. If None is selected and there are hour(s) where the temperature is below the Cutoff Temperature or where the heat pump will not meet the load, Ekotrope assumes that resistance heat will be used during those hours.
COP/AFUE/Adjusted Efficiency	For standard electric heat pumps with resistance heat backup, choose COP = 1. For dual fuel heat pumps, choose AFUE and enter the AFUE of the backup system.
Switchover/Cutoff Temperature	When a Backup Fuel Type is specified the label is Switchover Temperature, when None is specified it is Cutoff Temperature. This is the temperature at which the heat pump system (compressor) completely shuts down and backup heat takes over 100%. It is NOT the temperature at which backup heat starts to contribute. Above this temperature, Ekotrope will still assume that backup heat contributes as necessary to meet the load as the heat pump capacity goes down in colder outdoor temperatures. If unknown, Ekotrope recommends using 0F as a default. If None is specified for Backup Fuel Type and there are hour(s) where the temperature is below the Cutoff Temperature, Ekotrope will assume resistance heat will be used during those hours.
Use Default Supplemental Heat	If checked, Ekotrope estimates the supplemental heat based on estimated capacity and heating design load. If unchecked, the user can specify the supplemental heat capacity.
Supplemental Heat [kW]	Supplemental (not emergency) heat included with this heat pump.

Auxiliary Energy for Ground Source Heat Pumps

Closed Loop?	Is this ground source heat pump a closed loop system?
Estimate pump & fan power?	'When checked the auxiliary pump and fan power will be estimated in the manner described by ANSI/RESNET 301-2014 Section 4.3.5.
Fan Power	The power in watts of the fan of the air handler. If it's a radiant system, this should be 0.
Pump Power	The power in watts of the pump running the ground source loop. If it's a radiant system, you should add any additional wattage that's driving the radiant distribution loop. The heat pump units typically have an internal pump which should not be included here.

Distribution Type is Forced Air (Ductless)

Motor Type

Select whether the motor is variable speed (ECM) or single speed (PSC). Since fan energy is included in the "EAE" for furnaces and boilers, this will not affect fan energy. It will only affect duct efficiency calculations, which are calculated based on ASHRAE 152 - 2004 Seasonal Duct System Efficiency Algorithm

Desuperheater

To model a ground source heat pump equipped with a desuperheater:

Ground Source Heat Pump: Edit the equipment type, check Hot Water and specify an EF of 5. Then in the equipment set the % Hot Water Load Served using the guidance from this article and reduce the % Hot Water Load Served by other equipment so that the total adds to 100.

System Type (for Air Conditioners and Air Source Heat Pumps)

Equipment System Types

Select the equipment's system type from the available options: split system, single package, small duct high velocity, or unspecified. If the Air Conditioner or Air Source Heat Pump is rated in HSPF2 or SEER2, Ekotrope will use conversion factors specified in ANSI/RESNET 301 to convert HSPF2 to HSPF and SEER2 to SEER for the energy calculations. By default, equipment modeled with SEER2/HSPF2 will use the "unspecified" system type which uses similar conversion factors as the "split system" system type.