Solar Space heating

Lower temperature - more heat.

A conventional heating system is sized so that the boiler and radiators deliver enough energy to keep a house at 21°C when the outside temperature is -3°C. In other words, if the heating system is correctly sized, the boiler will be running continuously while the outside temperature
is -3°C.

However, -3°C weather is quite rare, so during most of the year a heating system is oversized for the prevailing conditions, leading to inefficiencies within the heating system. The most common is a condition known as boiler cycling.

Boilers are not normally designed to reduce output when the heat requirement of a building is lowered. They simply run "full-on" or off. This leads to an operation that is very like driving a car in stop-start traffic. As a consequence the efficiency drops off significantly. When the building is up to temperature, the boiler is switched off, however the internal boiler water cools, which causes the internal thermostat to fire up again, even if the heat is not required at that time. The boiler then cools again so this energy is being effectively wasted by heating the flue. This problem is exacerbated if the boiler has been oversized for the property.

Using a buffer tank to keep the boiler at maximum efficiency.

If instead of running a heating system directly from a boiler, a buffer tank is used to store the heat energy from the boiler and feed it to the radiators (or underfloor heating), boiler cycling can be eliminated (even for oversized boilers) and the efficiency of the heating system can be increased by about 25%.

Running the heating system at lower temperature.

Because radiator temperatures are designed to keep the building at 21°C when the outside temperature is -3°C. These temperatures can be reduced as the outside temperature rises. This give a further opportunity for energy saving, particularly if the buffer tank is also (pre)heated via solar panels. Solar panels also work more efficiently at a lower temperature.

Integrating Solar to the heating system

Solar panels work better at lower temperature and so are best suited to heating the bottom part of a buffer tank. The boiler can be used to heat the upper layers of water so that the heating is starting from the solar preheated water.

The heating circuit is fed from the top of the buffer tank and returned to the bottom, so that full use is being made of the heat stored in the buffer tank.

Outside Temperature Compensation

The warmer it is outside the lower the temperature require to operate the heating system. The control system reduces the boiler component of the heating system so that the buffer tank is only heated to the temperature required to bring and/or keep the building at a comfortable temperature. If the room temperature is too high, the radiators are cycled, instead of turning them off altogether. This reduces uncomfortable temperature swings in the building.

• Radiator temperature compensation
• Far less inefficient boiler cycling
• Maximum use of available solar energy
• Thermostatically controlled boost function

Please contact us for more details, plumbing diagrams etc.