This case study is written following Mr James’ request for a replacement solution to his existing heating and hot water systems.
The existing heating system was via a built-in warm air ducts and was installed when the house was built in 1980′s. The heating system was a Johnson Starley forced air ducted system fuelled by 28 sec heating oil (Kerosene) and the hot water was heated via a standard electric immersion heater cylinder. Despite years of good service the Johnson & Starley system had become expensive to maintain, noisy and had started feeding oil fumes through the ducting. More recently, the boiler developed an oil leak and whilst spares for this were hard to come by, the final straw was the exploding oil prices resulting in the customer contacting ACS Renewables for a free assessment.
Our initial brief was to find a cost effective solution to replacing the Johnson Starley forced air ducted system and electric heated hot water cylinder, Mr James’ property is off the gas grid and therefore a gas boiler was not an option and the high oil prices were not favouring an oil fired boiler either.
The house is of traditional cavity block and brick build, with cavity wall insulation, adequate loft insulation and all the windows are double-glazed, therefore is an ideal environment for an air source heat pump system, which would provide the property with energy efficient heating & hot water.
Mr James wanted to avoid retrofit work that would disrupt decoration, furnishings, carpets and floorboards, therefore we had to find a solution that would cause minimal disruption, and as there were no central heating pipework and radiators within the property to provide heat we took additional advise from our sister company Air Conditioning Solutions (UK) Ltd.
From this point we designed a scheme to suit all the requirements of the customer, using complimentary technology.
Air-to-air heat pump air conditioning ducted units were installed in to the loft void of the property to provide heat to the rooms (and the added bonus of cooling in the summer months), Air conditioning systems use air-to-air heat pumps, which remove heat from a room by condensing the rooms heat onto a cold fan coil on the indoor unit, this heat is transferred to the outdoor condenser via a refrigerant gas medium where a fan cools the gas within the sealed pipes.
If the system is reversed, heat from the outside air can be transferred again via the refrigerant into the room. A small amount of electricity enables heat captured from the outside air to be moved to indoors, making these systems over 300% efficient.
An Air to water Source Heat Pump boiler was specified to meet the family requirements using much less by way of electricity, providing plentiful hot water for storage using a typical copper cylinder.
For the ASHP boiler we used a Mitsubishi 5kW Ecodan to supply all of the domestic hot water for the whole house including two bathroom towel rails. In view of the compatibility of the existing cylinder, that was a 180 litre direct cylinder with no heat exchange coil. In its place, the customer opted for a 210-litre Ariston Primo Twin Coil Cylinder, which is more energy efficient and has better heat transfer. The whole system was connected using a Honeywell S plan wiring circuit, via a 24-hour 7-day programmer, and room stat controlling the towel rails.
This solution was achieved by avoiding as the customer requested minimal disruption by using the roof space and external walls thus avoiding any disruption to the living areas, this was an ideal project for a modern, low energy, air source heat pump and air conditioning systems.
With these systems in place the customer will now see considerable savings on his fuel bills and have the added benefit if cooling in the summer months.