Plant Loops


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 or hot/chilled water produced at a central plant (District).


Add separate Plant Loops for Heating and Cooling if your building has both heating and cooling, and/or condenser plant loop equipment. Then select and add all applicable distribution equipment types (Air Handler or Zone Equipment). 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.


 Heating Loop 

 Cooling Loop
 Condenser Loop

Energy Asset Score 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.


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) – Pull-down menu selections: match your installed system to one of  the  systems listed below and select the heating type accordingly.


Boiler – A closed vessel in which water or other fluid is heated. The heated liquid or steam is  circulated to air handling units, reheat coils in VAV boxes, or radiators to heat the space. If "Boiler" is selected,  additional pull-down menus for fuel type and draft type will be presented.


District – Hot water or steam produced at a central plant and delivered to building through underground  pipes.  

District Type   Pull-down menu selections: District Hot Water (default) or District Steam.


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



Boiler Draft Type – Pull-down menu selections: Mechanical (default) or Other Draft.

 

Equipment Details (present if a boiler is selected)


Energy Asset Score 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.


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) – Pull-down menu selections: match your installed system to one of  the  systems listed below and select the cooling type accordingly.


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. If  "Chiller"  is selected, additional pull down menus for chiller controls, compressor type, and condenser type will be  presented.  


District – Chilled water produced at a central plant and delivered to the building through  underground  pipes.


Chilled Water Reset – Check box: Should be checked if automatic chilled water supply  temperature setpoint controls are installed and in use. The chilled-water temperature reset saves chiller energy  by  raising the chilled-water temperature during times of low cooling demand, thereby reducing the pressure ratio in  the  chiller and raising the coefficient of performance.


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


I don't know – If selected, the chiller pump control will be set to constant primary by default.  


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. These systems can either be constant flow or variable  flow.  


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.


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. Note: A Condenser Plant Loop must be added before it is available as a selection from this pull-down menu.

 

Equipment Details (present if a chiller is selected)  


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 and select the Condenser Loop so the Chiller Plant Loop and Condenser Plant Loop are linked.


Energy Asset Score 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.


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


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


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.


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 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:


I don't know – If selected, the cooling tower fan control will be set to single speed by default.  


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.


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:


I don't know – If selected, the condenser pump control will be set to constant speed by default.  


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.


Add a Boiler – Button selection option to be used when creating a Water-Loop Heat Pump HVAC system.   A boiler must be added to the Condenser Loop for this system type.  When selected, Boiler Fuel Type, Draft Type, and Equipment Detail fields become available. 


Equipment Details (present if a boiler is selected)