Soil Heat Pumps
At a depth of 1 metre the ground temperature is fairly constant between 7 and 13 degrees Celsius throughout the year. The heat pump uses a ground loop (pipe) with a water and
glycol mix to "capture" some of this heat.
There are three styles of heat collection from the soil:
- Straight ground loop;
- Slinky ground loop;
- Compact collector ground loop
Straight Ground Loop
Ideally the ground loop consists of a single straight out and return line. However, it often consists of several loops brought together with a manifold and as seen from the graphic
below it doesn't necessarily have to be straight either!
Slinky Ground Loop
The Slinky ground loop substantially reduces the space required by coiling the groundloop back on itself.
Compact Collector Ground Loop
The patented compact collector allows a ground loop to be used where space is at a premium. The collectors can be buried flat to reduce the depth of the earthworks or vertically
to reduce the area needed for the panels.
Summer Cooling from Your Heat Pump
By adding one of our VBX units into the loft of your home you can provide effective summer comfort cooling. The unit draws hot air in from the house takes heat out and returns
the cooled air. The heat is fed into the ground loop via the heat pump and stored in the ground for later use.
Outside Air Heat Pump
The Optima heat pump is located outside your house. A silent-running fan draws in the outside air, and this heat is transferred to the heat pumps refidgeration circuit. The heat
pump converts this into hot water, which heats your house and domestic hot water.
There is no need for boring or digging. Just install the IVT Optima and you start saving money right away. IVT Optima can be connected to your existing heating system and provides
both heat and hot water. It can also replace your existing boiler and, together with an immersion heat and hot water cylinder, provide you with cheap, reliable heat for the future.
Bedrock Heat Pump
If there is bedrock at a reasonable depth under your plot, we recommend for very small plots bedrock heat.
An energy well, normally between 60 and 150 metres deep, depending on the energy needs of the house, is drilled in the rock. A hose package is lowered into the hole. The principle
is the same as for surface soil heat. A non-toxic liquid circulates in the hose. The temperature of the liquid is raised a few degrees by the heat in the surrounding rock. By compression
in the heat pump, the temperature of the liquid is raised and the heat is transferred to your radiators.
This thermal energy can also be used to heat the domestic hot water.
The effect of bedrock on your plot is minimal. It usually takes only one day to bore the hole.
Case Study
This detached property is in a rural location, comprising 230sqm, two bathrooms, four bedrooms and three reception rooms.
Underfloor heating is installed throughout. Three cooling fan coil units are connected to the ground heat collector to provide comfort cooling.
Ice Energy supplied an E7 heat pump and a 200 litre hot water storage tank. Two 55 metre trenches contain the ground loop heat collector pipe work. A total of 400 metres of heat
collector is installed.
The photograph below shows the installation of the heat pump and separate hot water tank.
The installation was carried out by the site plumbing contractors.
CASE STUDY 1 - Self-build in Coverack, Cornwall
The total annual energy consumption for this house is calculated at 32,400 kWh. This is based on a heat requirement of 45w/m sq. This is the energy required for central heating
and domestic hot water.
The cost for satisfying this heating load using oil-fired or gas-fired boiler, assuming the cost of domestic heating oil at 3.57p/kWh*, the cost of gas at 2p/kWh* and a boiler
efficiency of 75% will be:
Total energy cost (oil): 32,400 x 0.0357 x 1.25 = £1,446 per year
Total energy cost (gas): 32,400 x 0.02 x 1.25 = £810 per year
The cost for satisfying this heat load using Ice Energy heat pump, assuming electricity cost of 5p/kWh:
Electrical consumption for heat pump: 7,500kWh
Electrical consumption for additional heater: 620kWh
Total running cost (GSHP): 8,120 x 0.05 = £406 per year
The life expectancy of the heat pump is 25 years. During this time minimal maintenance will be required and there will be no reduction in the operating efficiency. The oil/gas
boiler will require an annual service and has a life expectancy of 12 years. During this time the boiler efficiency may diminish.
25-year running cost for heat pump:25 x 406 = £10,150 (average £406/year)**
25-year running cost for oil-fired boiler: £1,446 x 25 + (25 x 100) + 2400 = £41,050 (average £1,642/year)**
25-year running cost for gas-fired boiler: £810 X 25 + (25 X 100) + 2400 = £25,150 (average £1,006/year)**
*Source: Sept 05 - British Gas (gas) and Boilerjuice.com (oil)
**Assuming oil/gas boiler annual service cost at £100 and boiler replacement cost of £1200. Assuming NO increase in oil, gas and electricity prices. Assuming no decline
in boiler efficiency.
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