UK: A Daikin solar-powered heating, ventilating and air conditioning system is providing low cost, award-winning comfort to a Dorset business committed to renewable energy.
The combination of Daikin Altherma heat pumps, VRV IV Heat Recovery air conditioning and VAM ventilation units operate at virtually no cost because they are powered mostly by rooftop solar panels.
The installation has won the title of South West Renewable Energy Installer of the Year and came in second place for the small scale project of the year. It was shortlisted for Installer of the year in the Renewable Energy Association Awards 2016.
The systems serve the offices and vehicle workshop at Anglo American Oil Company’s head office and distribution depot on an industrial estate near Poole. The were installed before the company, which distributes specialist fuels and lubricants, moved into the new premises over a year ago – and performance figures for the first 12 months are impressive.
Managing director Anders Hildebrand wanted the premises to be heated and cooled as comfortably, efficiently and in as environmentally friendly a way as possible – without sacrificing any of the qualities expected in a contemporary new-build project.
“I wanted a solution that would create a working environment promoting high productivity levels, so temperature control and air quality were key. I also wanted to make maximum use of the Renewable Heat Incentive,” he said. (The Renewable Heat Incentive is a tax perk offered to UK businesses installing approved energy efficient equipment.)
Based on personal experience in Scandinavia, Anders Hildebrand also wanted underfloor heating – unusual in UK commercial steel-framed buildings. He also wanted to avoid any requirement for a mains gas connection.
He called in renewables specialist and Daikin Key Partner H2ecO, whose technical director Mike Stephenson worked with the Daikin design team to develop the solution.
“We decided to make it an all-Daikin installation to ensure compatibility, but there was no off-the-shelf solution to achieve what was required, Stephenson explained.
“The 342m² office component, over two floors, and the adjoining 189m² workshop have underfloor heating, with two RHI-eligible 16kW Daikin Altherma Low Temperature heat pumps as the heat source. The UFH piping is embedded in conventional screed in the offices, and in the concrete slab of the workshop.
“Once the slab is heated, there is surprisingly little impact on the air temperature when the roller shutter door is opened to move vehicles in or out.”
The heat pump also provides domestic hot water. Heat is transferred to the UFH and the coil of the DHW cylinder via a Hydrobox in the plant room.
The system is designed so that the UFH provides more than 98% of the facility’s heating demand – enabling the client to claim RHI payments for most of the space heating and DHW.
“An 8hp Daikin VRV IV Heat Recovery system provides cooling in the offices – as well as quick-response heating when needed, such as after Anglo American Oil Company’s Christmas shutdown. The system delivers via Daikin FXFQ-A Roundflow cassettes and FXZQ-A 600 square fully flat cassettes.
“The VRV system could, in fact, have met all the space heating requirement, but as heat recovery systems are currently not eligible for the RHI scheme, it did not fit the brief.”
The VRV system is interlocked to prevent it from ‘fighting’ the UFH system.
A VAM Heat Recovery ventilation unit provides fresh air throughout the offices, with minimal impact on indoor air temperatures.
All the systems are controlled through a Daikin i-Touch Manager.
To offset as much of the electrical demand as possible, a 30kWp solar PV array was installed. In the first year the solar array produced 30,000kWh of electricity – some 20% better than predictions derived from the government standard SAP methodology.
In the offices, heating energy consumption for space heating and DHW was 23,990kWh against electricity consumption of 6,041kWh – equating to a coefficient of performance of 3.97 and a ‘normal’ electricity cost of 2.5p/kWh of heat energy produced.
“The renewable element of the heat produced is about 75%,” says Mike Stephenson. “At the non-domestic RHI rate of 2.57p/kWh, heating would cost Anglo American Oil Company just 0.6p/kWh for 20 years if they were buying electricity from the grid.”
In the workshop, heating energy consumption was 17,187kWh against electricity consumption of 4,192kWh – equating to a CoP of 4.01.
“With PV generation taken into consideration, Anglo American Oil Company is effectively running its heating systems in the office and workshop at no cost. As the systems are consuming only 10,200kWh of the 30,000kWh produced, electricity costs over the whole site are significantly reduced – with potential for income from exporting surplus capacity to the National Grid,” he says.
One quirk of the installation is that the plant room, containing Hydrobox, DHW cylinder, UFH manifolds and inverters for the solar PV system also houses the company’s servers. To prevent this area from overheating and potentially affecting the electronic components, a Daikin multi split air conditioning system has been installed. It has a 3.5kW wall mounted inverter fan coil unit indoors, with a dedicated condensing unit outdoors – carefully positioned next to the Daikin Altherma heat pump to achieve a measure of heat recovery.