Plumbing Water Heater Energy Calculator
Budget actual unequal hot-water draws/feed temperatures with delivered setpoints and caller efficiency, not single mass×temperature scalar, standby loss or heating safety instruction.
Description
Sensible water-heating energy depends on volume, temperature rise and volumetric heat capacity.
Sensible water-heating energy depends on volume, temperature rise and volumetric heat capacity. Input energy includes an explicit efficiency.1
The returned values include Useful draw heat j, Total useful draw heat kwh, Modeled input heat kwh. The How section below explains the calculation, input rules and interpretation.
When to use Plumbing Water Heater Energy Calculator
Use Plumbing Water Heater Energy Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. Standby heat, phase changes and heater performance calibration are excluded.
Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.
How to use Plumbing Water Heater Energy Calculator and understand its results
- Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.
- Enter observedDrawVolumesLiters, observedColdFeedC, callerDeliveredHotWaterC, callerWaterHeatCapacityJLiterK, callerHeaterEfficiencyFraction using the field table and calculation rules, then run the tool.
- Read usefulDrawHeatJ, totalUsefulDrawHeatKwh, modeledInputHeatKwh. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| observedDrawVolumesLiters | Observed draw volumes liters | list of number | Required |
| observedColdFeedC | Observed cold feed c | list of number | Required |
| callerDeliveredHotWaterC | Caller delivered hot water c | list of number | Required |
| callerWaterHeatCapacityJLiterK | Caller water heat capacity j liter k | number | Required |
| callerHeaterEfficiencyFraction | Caller heater efficiency fraction | number | Required |
Enter aligned nonempty nonnegative volumes and finite temperatures with each delivery temperature at least its cold temperature, positive heat capacity in J/L/K and efficiency in (0,1]. Return per-draw heat, total useful kWh and input kWh.
J_i=liters_i×heatCapacity×(delivery_i−cold_i); inputKWh=sum(J_i)/3600000/efficiency Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| usefulDrawHeatJ | Useful draw heat j | list of number |
| totalUsefulDrawHeatKwh | Total useful draw heat kwh | number |
| modeledInputHeatKwh | Modeled input heat kwh | number |
{
"input": {
"observedDrawVolumesLiters": [
10,
20
],
"observedColdFeedC": [
10,
20
],
"callerDeliveredHotWaterC": [
50,
50
],
"callerWaterHeatCapacityJLiterK": 4200,
"callerHeaterEfficiencyFraction": 0.8
},
"output": {
"usefulDrawHeatJ": [
1680000,
2520000
],
"totalUsefulDrawHeatKwh": 1.1666666666666667,
"modeledInputHeatKwh": 1.4583333333333333
}
}Limitations and assumptions
Standby heat, phase changes and heater performance calibration are excluded.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Plumbing Water Heater Recovery Time Calculator: Recovery time divides required heat by net delivered heating power. Concurrent draw loss reduces that power. For a complementary task, use Plumbing Pool Heater Energy Calculator: Pool heating needs useful sensible heat plus losses during the delivery window. Explicit efficiency converts that delivered load to input power.
References
-
Plumbing Water Heater Energy Calculator — tool.io
Similar or alternative tools
- Plumbing Water Heater Recovery Time Calculator
Recovery time divides required heat by net delivered heating power. Concurrent draw loss reduces that power.
- Plumbing Pool Heater Energy Calculator
Pool heating needs useful sensible heat plus losses during the delivery window. Explicit efficiency converts that delivered load to input power.