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The iCapannini concept is to provide luxury living in a spectacular location, but at low cost to the owner and the environment.
The main house will secure its energy needs from a geothermal ground source heat pump. This will provide under floor heating/cooling and hot water supplemented by photovoltaic panels. The swimming pool and hot tub will also be heated through these sources and enhanced with a heat recovery system, minimising loss of energy. Solar panels will provide a electricity supply to all pumps and feed back into the grid when excess energy is produced, generating further income that can offset costs.
Heat pumps
Heat pumps are among the most efficient heating and hot water systems available today, supplying more energy than they consume by tapping into the freely available, inexhaustible solar energy stored in the earth, the ambient air or water and converting this for use in a heating system.
Approximately 75% of the energy needed by the heating system is extracted from the environment, so the only energy required is electricity needed to drive the heat pump compressor. This can be provided by the PV panels.
Every 1kWh of electricity used to run the heat pump, up to 4kWh of useful heat is provided, giving the heat pump an efficiency of up to 400%.
Low carbon heating solution
Whenever fossil fuels such as gas or oil are burnt, carbon dioxide is released. CO2 is the principle contributor to the greenhouse effect which is leading to long term climate change.
However as heat pumps extract as much as 75% of their heating energy from the environment, building carbon emissions for heating can be reduced by as much as 50% compared with gas fuelled heating systems.
This helps result in:
- Lower heating system carbon dioxide emissions
- Lower heating system running costs
- Low running costs, low ownership costs
But fuel costs are only part of the story. Unlike gas and oil based systems, heat pumps require no costly regular maintenance or annual safety inspections. And because a heat pump has a reasonable life expectancy of 20 – 25 years – typically twice that of a boiler – the investment costs can be recovered over a longer period, meaning the total ownership costs over the working life of the system are significantly lower.
The technology
A heat pump heating system consists of 3 components: the heat source, the heat pump itself and a heat distribution and storage system. Heat pumps are able to produce more energy than they consume by using the conventional refrigeration cycle to absorb heat from the environment and raise it to a suitable level for heating.
A large quantity of low grade energy absorbed from the environment is transferred to the refrigerant inside the heat pump (evaporator). This causes the temperature of the refrigerant to rise (even at sub zero temperatures) causing it to change from a liquid to a gaseous state.
The refrigerant is then compressed, using an electrically driven compressor, reducing its volume but causing its temperature to rise significantly. A heat exchanger (condenser) then extracts the heat from the refrigerant to heat water for underfloor heating and domestic hot water. After giving up its heat energy the refrigerant turns back into a liquid and after passing through an expansion valve can once again absorb energy from the environment, allowing the cycle to begin again
Ground source heat pumps extract heat from the earth all year round via ground heat collectors buried beneath the ground. Due to highly stable temperatures below the earth’s surface, ground source heat pumps provide high levels of efficiency for space and water heating all year round. Significant savings can be achieved from a 48kW system, which would cost approximately £40,000 to install:
The earth stores an enormous amount of solar energy from both solar radiation and rainfall. To extract this energy, ground collectors consisting of flexible poly ethylene pipes are buried in the earth, either horizontally or vertically. A mixture of water and anti-freeze is then circulated through the pipe loops, attracting the heat energy and transferring it to the heat pump.
Horizontal ground collectors
If a large enough land area is available, horizontal ground collectors provide an effective method of extracting heat from the ground. The pipework is buried at a depth of approximately 1.2m and spaced 0.75m apart. The land area required is dependent on both the capacity of the heat pump and heat conductance of the soil type in which the pipes are buried. As a space saving alternative to horizontal collectors, slinkies - consisting of coiled pipes buried in a trench – can be used.
Vertical boreholes
If land space is limited the ground collectors can be installed vertically in a borehole, drilled up to 100m deep in the ground. Multiple boreholes are commonly used in large installations where very high levels of heat extraction are required.
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