Harford Farm

We are installing two Vaillant 38kw Ground Source Heat Pumps each connected to five 130 meter deep boreholes. These will provide all the energy needs for the properties heating and cooling requirements, as well as all the heating for the swimming pool and pool complex.

To distribute heat into the property Under Floor Heating (UFH) will be installed throughout, the design and installation of this is fundamental to ensuring the highest efficiencies are achieved by the Heat Pump. Designing the UFH to ensure it heats the home with the lowest temperatures possible. Consequently when the outside temperature is at -3°, the flow temperature to the UFH will be approximately 35°, ensuring the home remains warm and toasty even on the coldest days of the year whilst achieving the highest energy efficiencies.

Building the house to be air tight helps keep the heat load of the property as low as possible, Mechanical Ventilation and Heat Recovery (MVHR) is then installed so the home can breathe. This provides the property with a constant fresh, clean, filtered air that supplies the living areas whilst also extracting the hot smelly air from the bathrooms, toilets and kitchen areas. The MVHR is designed to achieve around one third of an air change every hour in the house. To accomplish this air change rate the MVHR is designed to work at approximately 40 to 50% of its capacity; this makes the unit more efficient, quieter as well as increasing the air temperatures entering the building, all of which help the efficiencies of the building and reduce heat load.

Cooling the house is firstly done by cooling the air entering the property through the MVHR, this is done via two Cooling Coils that are connected to the inlet or supply air ducts. This constantly cools the whole property with gentle background Comfort Cooling. At the same time when there’s a cooling demand, the controls automatically increase speed of the MVHR unit up to 70 to 80% of its capacity (achieving approximately two thirds of an air change per hour), this helps the cooling by increasing the air flow throughout the property.

The coolant that chills the Cooling Coils comes from the stored cooled ground surrounding the boreholes that are connected to the Heat Pumps. This ground has been cooled after a winter of providing heating for the house and pool as well as all the hot water requirements. By simply circulating the fluid in the boreholes we can retrieve this stored coolant to provide the whole house with all its cooling requirements at a cost of approximately 50p a day.

In addition to the Comfort Cooling property also has 16 rooms that will have Air Conditioning installed; these rooms are controlled by the same thermostats that control the UFH. So for example, if a room’s stat is set to 20° the UFH will heat to that temperature then turn off. If the room’s temperature continues to rise even with the Comfort Cooling on to 22°, then the Air Con comes on automatically to keep the room temperature below 22°. This 2° dead band always remains, so if the room temperature is turned down at the stat to 18° then the cooling comes on at 20°, easy. The aim being when a room’s desired temperature is set our simple to use controls will keep it there, in effect creating a home with an automated renewable Climate Control system. The cost of running our complete cooling package including the Comfort Cooling on the hottest day of the year will be as little as £1.50 a day, indeed with a small Solar PV array installed it would cost nothing to run.

After some months of cooling the property the stored coolant will slowly diminish as the ground re-warms up, this rewarming of the ground we very much welcome as it helps the efficiencies of the Heat Pump for the forthcoming winter. But a warm ground of course reduces our cooling ability, which is not so good. So to ensure we achieve the correct temperatures required to offer a full Air Conditioning/Climate control solution, the cooling of the house is tied in with the heating of the Swimming Pool. We do this by hold off the heating of the pool water until there is a cooling demand in the house. Only then when the house asks for cooling do we start heating the pool, thereby getting the greatest efficiencies from the Heat Pump as it’s both heating the pool and cooling the house at the same time. By doing this we can control the coolant temperature and stored it to provide the Air Conditioning temperatures required of approximately 6° creating a perfectly balanced renewable heating and cooling system.

The property has other energy and money saving items such as the borehole and treatment plant to provide water for the irrigation to the grounds, water to flush the toilets and fill the swimming pool.

In summary, the total Be Green system guarantees this wonderful new home will have a simple to use fully automated, environmentally friendly, Climate Control system. It constantly monitors the home gently heating or cooling the environment whilst changing the air movement to individual rooms to suit the circumstances. All this ensures the property is always either perfectly warm or cool whilst creating the most comfortable and healthiest possible living space. This is all controlled at the touch of a button on the room stat, as part of the home automation system or on a beach somewhere with your mobile phone.

Below are some estimated cost of heating and cooling the home on an annual basis, as well as and providing all its hot water, cost exclude the swimming pool and pool complex.

• House heating cost for the year, heating demand 120,000kWh, cost of £3,700.00, CO2 output 18 tons
• Hot water demand, subject to occupants, 8,000kWh, costs of £400.00, CO2 output 4 tons
• Mechanical Ventilation and Heat Recovery, 5,000 kWh, running cost of £700.00, CO2 output 3.4 tons
• Comfort Cooling and Air Conditioning of whole house, 700kWh, cost of £100.00, CO2 output 0.5 tons
• Total annual running cost of Climate Control system £5,640.00, total CO2 output 27 tons

Approximate cost savings and CO? savings against a conventional Gas boiler

• Gas boiler running cost for above £6,800.00, CO2 output of gas boiler approximately 40 tons
• Comfort Cooling and Air conditions condenser and fans running costs, 11,000kWh, running cost of £2,300.00, CO2 output 9 tons
• Mechanical Ventilation and Heat Recovery, 5,000 kWh, running cost of £700.00, CO2 output 3.4 tons
• Total annual running cost of gas system £9,700.00, total CO2 output 52.4 tons

Total greenhouse emissions savings of over 25 tons of CO? a year Approximate running cost savings of heating and cooling system of over £5,000.00 a year

Technology Used in Project:

Underfloor Heating

The most efficient way to heat a home

Ground Source Heat Pump

Heating and Cooling from the ground

MVHR

Fresh Clean Filtered Airflow

Comfort Cooling

Whole House Climate Control

Swimming Pool Heating

Heating indoor or outdoor swimming pools

Solar PV

The simplest way of generating electricity