Renewable heating makes the difference

Two years after the start of the credit crunch, indications are that there is some light at the end of the tunnel for the UK economy. Although life is still tough out there for businesses, programmes of planned maintenance and refurbishment that have been mothballed in recent months are edging back onto the agenda, and forward-thinking building managers can gain an edge in a tough market by reducing heating costs with renewable heating like heat pumps.

It’s a buyer’s market

After two years of declining activity in the commercial property market, the latest figures point to some stabilisation in demand, particularly in the office sector, according to the latest figures from the Royal Institution of Chartered Surveyors (RICS). But with demand still close to historic lows and space available rising for the ninth successive quarter in Q2 2009, tenants are able to pick and choose when it comes to selecting space to occupy. Anything that makes a building more attractive to prospective occupiers is money well spent, so low running costs and low carbon footprint have great occupier appeal.

Since October 2008, those buildings with lower environmental impact are immediately apparent. Transparency on the issue of energy consumption in all non-domestic buildings is now ensured by Energy Performance Certificates which are mandatory for everything from small high street retailers to airports. Owners of newly built or refurbished business premises must receive an EPC before they accept a project from a builder and the documentation is also required on the construction, sale or lease of a property.

Focus on heating

So with heating a major contributor to both running costs and carbon emissions and occupiers generally favouring buildings with better environmental performance and operational costs, it makes sense for building managers to look carefully at their heating systems when the time for planned maintenance and refurbishment comes round.

A straight like-for-like replacement of existing heating systems is becoming less attractive as supplies of fossil fuels diminish and energy prices rise. And with further energy price rises looking likely, some traditional heating options may no longer even be viable long-term; owners of oil-fired systems saw the price of heating oil spike at 65p a litre in the summer of 2008 and may well be investigating alternatives that are more sustainable, both economically and environmentally. It makes sense to invest now in a renewable heating system with an expected lifespan of up to 25 years, rather than install a replacement conventional system which will need reviewing in another ten years.

Some businesses will still find the costs of a new renewable heating system off-putting. But building managers should bear in mind that the Renewable Heat Incentive comes into effect in 2011, offering financial support for locally-harvested renewable heat. And to minimise the impact of the initial capital costs of installation, leasing schemes like Dimplex’s Renewable Energy Finance can cover the complete project outlay and spread the costs over up to 15 years. Repayments can very often be met by the savings made on fuel bills, and payments from the RHI will also make a useful contribution.

Route to renewables

Air source heat pumps in particular offer great flexibility for retrofitting in a wide variety of applications both domestic (including multi-dwelling) and non-domestic. Air source technology has minimal space requirements compared with ground source, while relatively mild winter temperatures in the UK mean excellent levels of efficiency and performance are achieved throughout the year. 

Although it’s generally believed that air source heat pumps offer lower CoPs than ground source units, the latest technology is able to offer comparable performance, plus of course without the need for associated ground collector costs. And with models available for installation either in a plant room or outside, they offer great flexibility over system design.

Dimplex’s new range of high efficiency air source models offers high CoPs, even at low ambient air temperatures. The largest in the range, a 40kW model, offers a typical CoP of 3.9 at A2/W35 and 4.5 at A7/W35. In addition, some models are reversible and feature cooling capability, able to extract heat from the internal environment. Waste heat collected in this way can then be used for domestic hot water, or for heating a swimming pool, making them ideal for commercial applications such as leisure centres, where even greater savings on annual heating costs are achievable. It also saves the expense of running an additional separate cooling system and its associated maintenance.

Although this new generation of air source technology is fairly new to the UK, Dimplex heat pumps have been specified in a range of installations, two of which are outlined below.

Heat pumps in action

When the owner of a 17th century manor house in Oxfordshire wanted to refurbish it as a country house for paying guests, improving comfort levels in the many large rooms and insulating the heating system from future energy price rises were priorities, so heat pumps used in conjunction with underfloor heating were an ideal solution.

To meet the house’s high 110kW heating load, a system of three Dimplex LA 40 AS air source heat pumps for use in parallel was designed. Cheaper to install than ground source units and without the requirement for construction work to install ground collectors in the gardens and grounds, the units offer CoPs in excess of 4.0, even at low ambient air temperatures.

Although the plant room is located at the side of the house, it was decided to install the heat pumps in a wooded area about 100 metres distant, despite noise and vibration from the units being minimal. The controllers and all electrical equipment are located in secure housing close to the heat pumps, while remote access controllers have been located in the plant room which allow the system to be controlled from the house. This obviously required careful planning of the data transport, but this has proved to be no problem, showing the flexibility in system design which is possible with air source heat pumps.

Lowering costs

A prestigious Grade II listed hotel and leisure club near Cardiff has undergone a £1.2million refurbishment to combine facilities upgrades with the latest technology for lower energy costs and environmental impact, and Dimplex heat pumps have been installed in its leisure club to provide heating and hot water.

Lower fuel bills were a key objective for the leisure club, but equally important was the requirement to regulate the temperatures easily to accommodate the needs of different user groups from the 2,000-strong member base, so a system that could offer tight control as well as reducing carbon emissions was essential.

Two Dimplex LA 28 AS air source heat pumps have been installed; one to provide space heating and high demand hot water for the showers, the other for the swimming pool, with spare capacity for extension into the next phase of the hotel’s refurbishment programme.

The installation was completed last December and the system was immediately put to the test, with severely cold weather conditions setting in. However, the heat pumps successfully and quickly raised both the water and air temperatures with performance efficiencies exceeding forecasts, allowing the pool to be opened in time for the Christmas holidays. The leisure club has seen a major reduction in all its fuel bills since the heat pumps were installed, with energy consumption dropping by an estimated 50%.

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