Category: Non-renewable components

Describe your renewable hot water cylinder according to the example below:

  "storage_hot_water": {
    "name": "hot water tank",
    "volume_m3": 0.19,
    "immersion_kw": 3.0,
    "target_temperature_c": 55.0,
    "half_life_days": 2.5,
    "one_way_storage_efficiency": 0.95,
    "cost_install_gbp": 0,
    "cost_maintenance_pa_gbp": 0
  },

Set “volume_m3” to the cylinder’s capacity (1,000 litres = 1 m³) or, if you don’t have one, use a low value (e.g. 0.010).

The simulator takes energy from the cylinder according to your hot water demand. To estimate energy loss use “half_life_days”: the time for the hot water temperature to fall from “target_temperature” to fall midway to the internal ambient temperature (e.g. 37.5^oC if the ambient temperature is 20.0^oC). Use “one_way_storage_efficiency” to estimate lost hot water due to long or poorly insulated pipe.

The simulator maintains the cylinder at “target_temperature_c”. If a heating component does not have sufficient capacity, the next on the list is used to top up any deficit in the following order:

• solar thermal panels when active (i.e. during daylight), then;
• heat pump, if installed, then;
• boiler, if installed, then,
• immersion heater.

If the cylinder is part of your project, provision for its cost “cost_install_gbp” and annual maintenance if any in “cost_maintenance_pa_gbp”.

The simulator always assumes that your existing central heating system has a conventional oil or gas boiler.

To describe your boiler:

• use the “include” flag to include it, otherwise the simulator assumes your house has no boiler and is heated with electricity;
• include in “tariff” the name of the energy tariff it is using;
• give the heating capacity of your boiler in “output_kw”;
• give the boiler’s efficiency in “efficiency”;
• in “cost” include only any additional costs that will be incurred when using in “install_gbp”: normally it is zero. Also include its annual maintenance cost in “maintenance_pa_gbp”.