Hot Water Storage - update
Heatpunk helps you specify a hot water storage solution that's compatible with selected heat pump and sized based on property details. Once selected, you can view specs, domestic hot water (DHW) calculations and Legionella calculations.
You can fine tune these calculations for the specific requirements of the installation and share these details with customer in the technical report and customer proposal.
Adding hot water storage to a project
Hot water storage is selected in the Plan task.
Drag and drop hot water storage from the left-hand sidebar to place the cylinder in the plan. After placing it, you will be shown a list of recommended options.
Selecting a hot water storage option
When selecting hot water storage, you can select from the recommendations or scroll through the options on the left tosorted pickby frombrand theand type (pre-plumbed, standard, pre-plumbed slimline, slimline and horizontal cylinder options.horizontal).
When you have an option selected, to the top right, you will see spec information and bottom right Midsummer stock information. If your account is connected to Midsummer, you will also see your specific pricing.
Hot
How recommendationsare the recommended options chosen?
Recommendations are based on compatibility with the heat pump and are sized according to the number of bedrooms and occupants. Adjust the number of bedrooms/occupants and click Recommend to get updated recommendations.
How is the recommended volume calculated?
This is calculated using the MCS method for DHW demand:
Recommended volume = 45 * N
where N is the greater of:
- The number of rooms + 1
- The number of known occupants
Editing hot water storage in a project
You will also have the following options to the top right of the Hot water tab on the right-hand sidebar:
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Pencil icon: Edit hot water selection |
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Eye icon: Show/hide DHW energy and Legionella purge demand, weight, standing heat loss, coil size and immersion heater size. |
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Bin icon: Remove hot water storage |
Hot water storage details and DHW calculations
You can view details for the chosen hot water storage in the Hot water tab.
- Model
- Nominal capacity (ℓ)
- Cylinder re-heat time (min)
- Vdraw/Mix down volume (ℓ)
On the cylinder, click ⋯ three dots > Show all details to view the following:
- DHW energy demand (kWh/year)
- Legionella Purge Demand (kWh/year)
- Weight (empty | full) (kg)
- Standing heat loss (kWh / Hrs)
- Coil size (m2)
- Immersion heater size (kW)
These details are then given in the Hot Water Calculations page of the Technical report and Customer proposal for you to share with the customer.
How is DHW energy demand calculated?
DHW energy demand is calculated using the storage temperature, supply temperature, number of occupants and the water needed per person.
First the volume of water needed per year is calculated with the following calculation:
Volume per year = number of occupants * the water needed per person * 365
Noting that for water, volume (L) = mass (kg). Then using the specific heat capacity of water (kJ/kg°C), this is converted to kWh/year:
DHW energy demand = 4.2 * (1/3600) * mass per year * (storage temperature - supply temperature)
Adjusting DHW and Legionella calculations
These calculations can be fine tuned by editing the Hot water preferences on the Hot water tab:
This will give you the following options to edit under Hot water storage settings:
- DHW Storage Temperature (°C)
- Difference between flow temperature while providing hot water and storage temperature (°C)
- Flow Temperature while providing hot water (°C) (This is calculated based on the two previous inputs)
- Draw Water Temperature (°C)
- Supply Water Temperature (°C)
- Pipework Efficiency (%)
- Water used per person per day (ℓ)
Under Legionella settings, you then have these options:
- Legionella purge required (Yes/No)
- Legionella purge frequency (Weekly/Daily)
- Legionella heat source (Immersion/Heat pump)
- Legionella purge temperature (°C)
Changes to these settings will only affect the selected design option.