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Hot Water Storage

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 Heat Pump task. When you first enter the Heat Pump task, after selecting a heat pump you will be shown a list of recommended options.

If you initially did not include hot water storage in the project, navigate to the Heat Pump task, on the left below the 'Heat Pump Load' section you will see the 'Hot Water Storage' section. Click the pencil icon to add hot water storage. 

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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 to pick from the pre-plumbed, standard, pre-plumbed slimline, slimline and horizontal cylinder options.  Cylinders that are incompatible with the selected heat pump say 'incompatible with selected heat pump' in red text. 

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 water storage recommendations 

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. 

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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 

You will also have the following options to the top right of the Hot Water Storage section: 

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Pencil: edit selection

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Cog: edit hot water storage settings 

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Bin: remove hot water storage 

System details and DHW calculations

Once you've selected a hot water storage option, you can see the option in the Hot Water Storage section of the Heat Pump task. Here you will see all the specifications and the following calculations:

  • Cylinder re-heat time (min)
  • DHW energy demand (kWh/year)
  • Vdraw/Mix down volume (ℓ)
  • Legionella Purge Demand (kWh/year) 

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. 

Adjusting DHW and Legionella calculations

These calculations can be fine tuned by editing the hot water storage settings. Clicking the cog icon will give you the following options to edit: 

  • DHW Storage Temperature (°C)
  • Difference between flow temperature while providing hot water and storage temperature (°C)
  • Flow Temperature while providing hot water (°C)
  • Draw Water Temperature (°C)
  • Supply Water Temperature (°C)
  • Pipework Efficiency (%)
  • Water used per person per day (ℓ) 

Under 'Legionella', you then have the following options:

  • Legionella purge required (Yes/No)
  • Legionella purge frequency (Weekly/Daily)
  • Legionella heat source (Immersion/Heat pump)
  • Legionella purge temperature (°C) 
  
  
  
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