Having established a reasonable flow of business from the domestic market through our expanding distributor and trained installer network, we are now looking to promote the benefits of solar thermal systems to the commercial sector. Our own brand range of Suntech Solar Super Heat Pipe collectors have recently been specified for a new build project where many aspects of energy saving technologies are being incorporated.

 It has been slow coming but towards the end of last year we started to see an increase in inquiries from the commercial and business sector, as well as from housing associations and private builder developers who fall into the 10% Merton Rule on new build projects over 1,000m2.

 The pay back for commercial and business is far quicker than for a domestic home. What all large or small businesses need to understand is that cold water now needs to be heated to above 60°C. Solar thermal loves working at low temperatures so can easily raise that incoming water to 30°C, still only warm, but that rise in temperature would have been achieved without the use of costly fossil fuel. A solar thermal collector, such as the Suntech Solar range, can provide about 50% of a business’s hot water needs, working as a pre-heat system. The biggest market yet untapped is in the food and catering industry.

Taking care of it

One recent project we have undertaken was for a new £5 million private care home being constructed opposite Fontwell race course in Sussex. The brief by the client was as follows:

 (1) To provide pre-heated water through a mix of solar thermal and air to water heat pumps to be located on a flat roof section and pitched south facing roof.

 (2) The pre-heated water to service 29 private apartments within the care home communal areas, kitchens and laundry.

 (3) To design, supply and fit 3,000m2 of underfloor heating with each apartment individually controlled by thermostats wired to actuators.

 (4) For the car parking area to be lit by solar powered LED standalone lighting.

 (5) For the landscaped garden to also be lit by standalone solar commercial lanterns.

 (6) All internal lighting to be of CFL and LED.

It seemed a simple enough brief, so we decided to use this project for the launch of our recently launched Suntech Solar Commercial range.

Latest technology

The project is now nearing completion and this is how it’s all designed to work:

 The 20 x 30 evacuated triple coated tubes (600 tubes) incorporating the latest in Super Heat Pipe technology were installed in three separate configurations.

 Two banks of 4 x 30 tubes were installed on the tiled roof at the front of the two story building.

 A further two banks of 6 x 30 tubes also installed on the second of the two pitched roofs, with a third bank of 2 x 30 tubes to complete the numbers.

 No Glycol/water fluid solution is required for these Suntech Commercial collectors, due to the overall design and innovation hidden inside. The key difference between these collectors and the common flat plate is that the Super Heat Pipes already have a freeze protection solution inside, but only as a tablespoon of fluid per heat pipe.

Well connected

All the plumbing pipe for the Suntech collectors is a continuous 20mm stainless steel flexible pipe, avoiding any potential leaks from joining copper pipes. All pipework was pre-insulated to maintain the temperature reached in the manifolds to the two tanks. The pipework from the heat pumps was Pex-al-Pex 25mm diameter, pre-insulated, eliminating any joints between the roof and connection to the hot water tanks.

 The two 1,700 litre all-copper thermal store Powertech designed vented water tanks have each been fitted out with 10 meters of 1 inch finned copper coil pipes, with both tanks connected together. Each tank is also fitted with ¾ inch finned copper coils for the solar array and heat pumps to operate as closed loop systems.

The two thermal stores act as a pre-heat to the four large commercial gas boilers located in a second plant room on the first floor. The mains cold water enters through the finned copper pipe in the first store, then passes to the second store on its way to the gas boilers, which circulates the water as a ring main, with a draw off to each apartment to cut hot water waste while waiting for it to arrive.

Savings plan

Projected energy savings compared with using 100% gas/oil for heating the water from solar has been calculated out at around 5,000-6,000kW hours a year, resulting in an annual CO2 emissions reduction of 10 tonnes a year. A German controller will calculate the kWh of heat generated at low temperatures and high temperatures every time the circulating pumps come on to deliver the 30 litres of water in the solar headers to the two storage tanks.

 At peak Watt hours of the day it’s very possible that the collectors will continue to raise the temperature in the headers as fast as the heat is being lost in heating the tanks.

Supporting role

Located on the flat roof sections between the two pitched roofs are two 10.6kW air to water heat pumps. The heat pumps are designed to operate 18 hours a day, providing support and back up for the solar collectors. They will use around 5.6kWh of electricity, part off peak delivering 15kWh of heated water up to 55°C while in compressor heat producing mode.

 The underfloor heating throughout the ground floors and some first floors is to be heated by gas boilers to provide a constant guarantee of all year round heating.

Outside the space heating and hot water installation, in the gardens and parking area, solar powered lighting is being installed, designed for all year round lighting around the landscaped gardens and car parking area. The solar PV LED stand alone lighting features a battery pack which can provide light from 120 LED lamps for up to 24 hours if there is not sufficient sunlight during the day.