Add a Plant Loop if the HVAC System of your building includes a central hot water, chilled water or condenser water supply. The source may be an on-site condenser, chiller or boiler. District heating and cooling systems are exempt from TSPR requirements and not available to analyze through the tool. Add separate Plant loops for heating and cooling if your building has both hot water, chilled water, and/or condenser water plant loop equipment. 

 

Plant loop component entries   must have at least one equipment schedule entry (see the Mechanical Equipment page for details).  If multiple plant equipment entries serve the same plant loop, the equipment schedules will auto calculate weighted averages for heating and cooling efficiencies.  Plant loops may be added and edited from either the Mechanical Equipment screen, or the Heating and Cooling screen.

 

Follow the steps below to add plant loops.  Refer to the TSPR data entry options for details.  


Heating Loop 

Cooling Loop

Condenser Loop

   

After completing Plant Loop inputs, select and add all applicable distribution equipment types (Air Handler or Zone Equipment) served by the plant loop(s). If the HVAC system of your building does not include plant loops, then proceed directly with adding Air Handler (e.g. packaged roof top air conditioner or heat pumps) or Zone Equipment (e.g.  packaged terminal units) components.

 

Adding Plant Loops for TSPR 

 

  1. Select the ‘+’ (Add) icon from the Plant Loops sidebar option on the Heating and Cooling screen, or the Add Plant Loops button on the Plant Loops tab on the Mechanical Equipment screen  
  2. Enter a descriptive name for the Plant Loop or use the default component text and counters
  3. Select a Plant Loop Type and a Pump Power value.   
  4. Enter a descriptive name for the Plant or use the default component text and counters
  5. Select a Plant Type
  6. Select a Fuel Type Boilers, Compressor Type, Condenser Type, and Chiller Pump Control for Chillers, or Condenser Plant Type for Condensers
  7. Create a new Mechanical Equipment Schedule entry by entering a descriptive name, number of pieces of equipment and rated capacity and efficiency values. Select the blue ‘Add Equipment’ button to add additional entries. or 
  8. Assign previously created equipment by selecting the Attach icon (paper clip)
  9. Select the green ‘Create’ button to add the new Plant Loop

   

TSPR Data Entry Options for Heating Plant Loops

 

Loop Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.

 

Pump Power – Specified using the power-per-unit-flow method (W/gpm). This is defined as the electric power of the pump divided by the flow at design conditions.

 

Plant Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text. 

 

Plant Type (Heating Plant Loops) – Select “Boiler” from the pull-down menu selections.  Additional pull-down menus for Fuel Type and Thermal Efficiency will be presented.

 

Boiler – A closed vessel in which water or other fluid is heated. The heated liquid is circulated to air handling units, reheat coils in VAV boxes, or radiators to heat the space.

 

Fuel Type – Pull-down menu selections: Natural Gas, Electricity, Fuel Oil, or Propane

 

Calculated Efficiency (Heating)  – Auto calculated to remove the supply fan energy and displayed from values entered in the mechanical equipment schedule and displayed from values entered in the mechanical equipment schedule. Represents the percentage of the rate of heat delivered to the rate of energy input.  A minimum of 60% may be entered; typical values are between 74%-92%. 

   

TSPR Data Entry Options for Cooling Plant Loops

 

Cooling plant loop equipment here refers to assemblies that normally include an evaporator or cooling coil and a compressor and condenser combination.

 

Loop Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.

 

Chiller Pump Control – Chilled water pumping systems generally fall into one of two categories: primary-only, and primary-secondary. Pull-down menu selections:

 

Constant Primary – Select if a primary-only system where one set of pumps circulates chilled water between the chiller(s) and the air handler(s) is in use. TSPR tool currently supports only constant flow systems.  

Constant Primary; Variable Secondary – Select if a primary-secondary system where the primary pumps circulate chilled water through the chiller(s), and the secondary pumps draw from that loop to circulate chilled water  to the air handler(s) is in use.

 

Pump Power – Specified using the power-per-unit-flow method (W/gpm). This is defined as the electric power of the pump divided by the flow at design conditions.

 

Plant Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.

 

Plant Type (Cooling Plant Loops) – Select “Chiller” from the pull-down menu selections.  Additional pull-down menus for compressor Type, condenser Type and Efficiency will be presented.

 

Chiller – Refrigeration systems that provide cooling through either air-cooled devices using a fan to force air over condenser coils, or water-cooled devices that fill condenser coils with circulating water.

 

Chilled Water Reset – Check box: Should be checked if automatic chilled water supply temperature setpoint controls are installed and in use. The chilled water reset (CHW) works by raising the chilled water supply air temperature during periods of low cooling loads thus improving chiller operational efficiency.

 

Compressor Type – Pull-down menu selections: Scroll/screw (default); Centrifugal; Reciprocating

 

Condenser Type – Pull-down menu selections: Air (default); Water. If water is selected, an additional pull-down menu for Condenser Loop will be presented.

 

Condenser Loop – Pull-down menu selections: Cooling Tower.  A Condenser Plant Loop with Cooling Tower selected as the Condenser Plant Type must be added before Cooling Tower is available as a selection from this pull-down menu.


Note: For water-cooled chillers (e.g. present with VAV with Hot-Water Reheat and VAV with Electric Reheat systems), first add a Condenser Plant Loop with a Cooling Tower Plant, then add a Cooling Plant Loop with a Chiller Plant, select Water as the Condenser Type, and select the Condenser Loop so the Chiller Plant Loop and Condenser Plant Loop are linked.

 

Calculated Efficiency (Cooling)  – COP is auto calculated to remove the supply fan energy and is displayed from Rated Efficiency values entered in the mechanical equipment schedule.   Efficiency of the cooling system in coefficient of performance (COP) is the ratio of the rate of heat removed to the rate of energy input, in consistent units, for a complete refrigerating system or some specific portion of that system under designated operating conditions.  Where multiple chillers serve a chilled water plant loop, the tool will calculate a capacity weighted average efficiency. 


Note: Chiller efficiency entries should be the full load value from Path B.

 

     

TSPR Data Entry Options for Condenser Plant Loops

 

Loop Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.

 

Condenser Pump Control – Condenser water pumps circulate water between the chiller and the cooling tower. Most cooling plants use constant speed condenser water pumps piped in parallel. Pumps with variable speed drives (VFDs) may also be used. VFDs are controlled to maintain a setpoint of some measured variable, e.g., temperature or pressure. Pull-down menu selections:

 

Constant Speed – Select if the cooling plant uses constant speed condenser water pumps.

Variable Speed – Select if the cooling plant uses variable speed condenser water pumps.

 

Pump Power – Specified using the power-per-unit-flow method (W/gpm). This is defined as the electric power of the pump divided by the flow at design conditions.

 

Plant Name – Default component text and counters are automatically added. This entry may be edited to include other descriptive or identifying text.

 

Plant Type (Condenser Plant Loops) – Pull-down menu selections: match your installed system to one of the systems listed below and select the condenser plant type accordingly.

 

Ground Heat Exchanger – A ground source heat pump (GSHP) system that uses a ground heat exchanger component to extract the heat from the ground in winter or returns it to the ground in summer.

Cooling Tower – A condenser water system that uses a cooling tower component where heat is ultimately rejected when transferring heat from the building to the outdoors. If selected, the additional input fields below will be presented.

 

Cooling Tower Fan Control – Many older cooling towers use constant speed fans that cycle to maintain the condenser water supply temperature setpoint. Cooling tower fans that use variable speed drives (VFDs) to vary the speed of the fans to maintain the condenser water supply temperature setpoint yield energy savings with no associated pump penalty or sacrifice in performance. Pull-down menu selections:

 

Single Speed – Select if constant speed cooling tower fans are used.

Variable Speed – Select if variable speed cooling tower fans are in installed and in use.

 

Cooling Tower Design Range Temperature – This numeric field specifies the range temperature (˚F) at design conditions. It is defined as the inlet water temperature minus the outlet water temperature.

 

Cooling Tower Design Approach Temperature – This numeric field specifies the tower approach temperature (˚F) at design conditions. It is defined as the outlet water temperature minus the inlet air wet-bulb temperature.

 

Cooling Tower Efficiency – Efficiency of a cooling tower expressed in gallons per minute (gpm) of condenser water flow per fan motor horsepower (hp). 

 

Add a Boiler – Button selection option to be used when creating a Water-Loop Heat Pump HVAC system, and when Cooling Tower has been selected as the Condenser Plant Type.   A boiler must be added to the Condenser Loop for this system type.  When selected, input for Fuel Type is displayed.   An equipment schedule entry must be added for the boiler (see steps above for instructions). 

 

Fuel Type – Pull-down menu selections: Natural Gas, Electricity, Fuel Oil, or Propane.