Mechanical Plant Results

load model results, central plant sizing, plant sizing, equipment selections

Patrick Chopson avatar
Written by Patrick Chopson
Updated over a week ago

A mechanical plant consists of different components such as chillers, boilers, pumps, and cooling towers that are connected to air systems and provide chilled and hot water to those components.

They are often the largest single piece of equipment on a project along with one of the highest cost items of the mechanical package. Finally, they have a large impact on energy consumption over the life of a building. Given their importance in size, cost, and energy sizing Mechanical Plants correctly is of critical importance to sustainable building design.

This article includes a brief overview of the mechanical plant results for each component.

Electric Chiller Cooling Plant

Various information is included in mechanical plant results for chiller plant. This includes plant information such as fluid type, pumping strategy, and minimum & maximum fluid temperature. Chiller specifications such as chiller type, peak capacity, and chilled water flow rate can be reviewed. 'Capacity check' indicates the engineering check value for chiller capacity. Chiller plant results also include pumping information for both primary and secondary pumps serving the plant, such as pump type, pump peak power, and fluid flow rate. Following items are included in the plant results for the Electric Chiller Plant:

Name: A unique name for the equipment can be provided

Type: determines what type of condenser will be modeled with this chiller

Peak Capacity[Btu/h (IP) | Watts (SI)]: This numeric result field contains the “maximum” chiller capacity in watts.

Chilled Water Flow Rate [GPM (IP) | L/S (SI)]: for a variable flow chiller this is the maximum water flow rate and for a constant flow chiller this is the operating water flow rate through the chiller’s evaporator.

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design cooling capacity per building area.

Cooling Tower Condenser Plant

This section includes information about the plant type, fluid type, pump strategy, and minimum & maximum fluid temperature. The cooling tower specifications such as the cooling tower type, nominal capacity, fluid flow rate, air flow rate, and plant capacity engineering check can be reviewed. Also, the pumping information such as type, peak power, and fluid flow rate is included. Following items are included in the plant results for the Cooling Tower Condenser Plant:

Name: The unique name for the equipment

Type: this field indicate the cooling tower type. result can be single speed or variable speed cooling tower

Nominal Capacity [Btu/h (IP) | Watts (SI)]: This numeric result field contains the “nominal” heat rejection capacity of the cooling tower in watts.

Fluid Flow Rate[GPM (IP) | L/S (SI)]: This numeric field contains the design water flow rate through the tower. This value is the flow rate of the condenser loop water being cooled by the tower (not the flow rate of water being sprayed on the outside of the heat exchange coil)

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design condenser plant capacity per building area.

Hot Water Boiler Heating Plant

Boiler plant includes electric or gas-powered boiler and pumps to serve the plant. The result page includes plant details such as fluid type, pumping strategy, and minimum & maximum fluid temperature. Boiler specifications such as fuel type, peak capacity, and hot water flow rate are provided under the boiler section. Boiler plant results also include pumping information for both primary and secondary pumps serving the plant, such as pump type, pump peak power, and fluid flow rate. similar to other mechanical plants, capacity check can be reviewed to ensure the validity of results. Following items are included in the plant results for the Hot Water Boiler Heating Plant:

Name: A unique name for the equipment can be provided

Fuel Type: specifies the type of fuel used by the boiler. Options are: Electricity, Gas, Propane, Fuel Oil #1, Diesel

Peak Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design heating capacity of the boiler.

Hot Water Flow Rate[GPM (IP) | L/S (SI)]:This numeric field contains the design hot water volumetric flow rate.

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the boiler design heating capacity per building area.

District Cooling Plant

District cooling plant results include plant details such as fluid type, pumping strategy, and fluid temperature minimum and maximum value. District cooling peak capacity, capacity engineering check, and, primary pump information are also included. Following items are included in the plant results for the District Cooling Plant:

Name: The unique name for the equipment

Peak Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design cooling capacity of the district cooling system.

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design cooling capacity per building area.

District Heat Plant

District heating plant results include plant details such as fluid type, pumping strategy, and fluid temperature minimum and maximum value. District heating peak capacity, capacity check, and primary pump information such as pump type, peak power and fluid flow rate are also included. Following items are included in the plant results for the District Heating Plant:

Name: The unique name for the equipment

Peak Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design heating capacity of the district heating plant.

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design heating capacity per building area.

VRF Heat Pump and Heat Recovery Plant

VRF plant results include plant details such as cooling capacity, heating capacity, condenser air flow rate, condenser pump power and VRF plant capacity check to ensure the validity of results. following items are included in the plant results for the heat pump and heat recovery:

Cooling Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design cooling capacity of the heat pump.

Heating Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design heating capacity of the heat pump.

Condenser Air Flow Rate: This field represents the air flow rate passed through the condenser

Condenser Pump Power[Watts (IP) | Watts (SI)]: this field includes the condenser pump power.

Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design capacity per building area.

Ground Source Heat Pumps

GSHP results provide information related to capacity, peak power and flow rates required to meet the load calculated.

Water to Water Heat Pump - Cooling

Name: The unique name for the equipment

Peak Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design heating capacity of the heat pump.

Peak Power [Watts (IP) | Watts (SI)]: This output variable represents the compressor power required to run the heat pump.

Load Side Flow Rate [GPM (IP) | L/s (SI)]: This output variable represents the average fluid flow rate through the load side coil.

Source Side Flow Rate [GPM (IP) | L/s (SI)]: This output variable represents the average fluid flow rate through the source side coil.

Cooling Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design cooling capacity per building area.

Water to Water Heat Pump - Heating

Name: The unique name for the equipment

Peak Capacity [Btu/h (IP) | Watts (SI)]: This output variable represents the design heating capacity of the heat pump.

Peak Power [Watts (IP) | Watts (SI)]: This output variable represents the compressor power required to run the heat pump.

Load Side Flow Rate [GPM (IP) | L/s (SI)]: This output variable represents the average fluid flow rate through the load side coil.

Source Side Flow Rate [GPM (IP) | L/s (SI)]: This output variable represents the average fluid flow rate through the source side coil.

Heating Capacity Check [Btu/h/ft² (IP) | Watts/m² (SI)]: This output variable represents the design heating capacity per building area.

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