Water Source Heat Pumps
What is a Water Source Heat Pump
All the advantages and high efficiencies of a ground source heat pump without the costs of ground works – that’s water source heat pumps. Water has a high specific heat capacity that means it will slowly absorb or release heat. The best ground for collecting heat is saturated with water so it will absorb the heat during the summer months to be retained through to winter allowing this energy to be harnessed when we require it the most.
By using the same processes as a ground source collector with the ground collector simply placed within a body of water such as a pond or a stream with both sufficient depth and flow rate.
There are two main types of water source heat pumps; closed loop or open loop.
Closed loop: this solution features the same collector type as ground source, with a super chilled solution passes through a slinky or horizontal pipe absorbing heat from the surrounding water body as it goes.
Open loop: this solution simply takes fluid from the water source itself, pulled through a series of filters and is then through the heat pump itself. The collected water is then put back into the water course a little further away.
With all water source heat pumps it is important that the water source does not dry up. This is particularly important if open loop bore holes are being used; no water means no heat.
Renewable Heat Incentive
The Renewable Heat Incentive (RHI) that water source technology attracts is the highest of the heat incentives. This is in part to help offset the extra installation costs associated with this solution verses say air source.
Currently the tariff rate for new ground source installations is 20.46p/kWh* for domestic installations with an upper limit of 30000kWh for deemed water and space heating combined. If your property's EPC figure is higher than this payments are simply throttled back to this figure.
Below is an example of what this equates to in terms income for a standard 3-4 bed detached property;
Property size = 200m²
Property age = 1980’s
Property insulation standard = filled cavity and required 250mm of loft insulation
Payment per quarter = £1,200
Payment over 7-years = £33,600 (excludes year on year inflation percentages)
* Tariff rate taken from Ofgem with the rate running from 1st April until 30th June 2018.