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.
Description
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
Default Priority
Low
Message
Hot water system/Boiler heating load, cumulative heating energy consumption, cumulative heating energy cost and GHG emission are calculated.
Rule Template
Insight Type: Energy
Trigger Type: Active High
Inputs
| 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 | $/mmBTU | The cost of thermal energy mm BTU. This is set to 3. |
Notes
1. Only one “Flowrate”, [LPS] or [GPM] is needed.
2. Only one “Boiler Status” is required when this rule is implemented for a boiler. The rest “Boiler Status” should be set to 0.
3. The input(s) that is(are) not used should be set to “0”.
4. Expected values for “Pump Speed” inputs are “100” if they are constant speed pumps or not available.
5. Expected values for “Pump Status” inputs are “0” or “1”.
6. Expected values for “Boiler Status” inputs are “0” or “1”.
7. CO2 emission factor is from U.S. Environmental Protection Agency.
Default Values:
Const. – Specific Heat of Water [kJ/kg°C]: 4.2
Const. – Natural Gas CO2e Emissions Factor [(kgCO2)e/mmBTU]: 52.9
Const. – Boiler Efficiency: 90%
Const. – Thermal Energy Cost ($/mmBTU): 3
