Hot water system/Boiler energy consumption calculation

Objective/ Method/Outcome

Objective: Calculate the hot water systems energy consumption.

Method: Uses the heat capacity equation to calculate the Hot Water System/Boiler energy consumption.

Outcome: This rule generates CTLs.

This rule calculates hot water system/boiler energy consumption by using heat capacity equation. Four calculated trend logs are generated:

1. Heating Load (BTU/hr)

2. Heating Energy Consumption(CUSUM)

3. Heating Energy Cost(CUSUM)

4. Heating GHG Emissions(kgCO2e)(CUSUM)

This rule is part of the CopperTree Standard rule-set

Low

Hot water system/Boiler heating load, cumulative heating energy consumption, cumulative heating energy cost and GHG emission are calculated.

Insight Type: Energy

Trigger Type: Active High

Input	Unit	Tags	Description
Supply Water Temperature	°	Hot Water Supply Temperature	The recorded hot water supply temperature
Natural Gas CO2e Emissions Factor	kgCO₂e/mmBTU		The set natural gas emission factor. By default it is set to 52.9.
Flowrate	GPM	Hot Water Supply GPM	The recorded hot water supply in GPM.
Pump Rated Flowrate	GPM		The recorded pump flowrate.
Pump Speed		Hot Water Pump VFD Speed
Return Water Temperature	°	Hot Water Return Temperature	The recorded return water temperature
Boiler Efficiency			The set boiler efficiency which is set to 90% by default.
Thermal Energy Cost	$/mmBTU		The cost of thermal energy mm BTU. This is set to 3.

1. Only one “Flowrate”, [LPS] or [GPM] is needed.

2. Only one “Boiler Status” is required when this rule is implemented for a boiler. The rest “Boiler Status” should be set to 0.

3. The input(s) that is(are) not used should be set to “0”.

4. Expected values for “Pump Speed” inputs are “100” if they are constant speed pumps or not available.

5. Expected values for “Pump Status” inputs are “0” or “1”.

6. Expected values for “Boiler Status” inputs are “0” or “1”.

7. CO2 emission factor is from U.S. Environmental Protection Agency.

Default Values:

Const. – Specific Heat of Water [kJ/kg°C]: 4.2

Const. – Natural Gas CO2e Emissions Factor [(kgCO2)e/mmBTU]: 52.9

Const. – Boiler Efficiency: 90%

Const. – Thermal Energy Cost ($/mmBTU): 3