Solar Hot Water Components  

Home Page Solar Hot Water SHW Performance data Grid connect PV Solar Electricity Links

  The details of the main components used in my installation are given below. The system is made up of the collector on the roof, the Solar hot water cylinder, the expansion vessel, and the control board. The installation consisted of : One day to replace the Hot water cylinder & put the frame for the tubes on the roof, a couple of evenings to do the pipe work in the house. Then one more day to finish the pipework on the roof, install the tubes and test the system. Total cost of all parts was 1,800. With NO labour cost. For performance data see SHW performance page  
  Clare carrying tubes up ladder  
    Half the tubes in place  
  Fixing frame to roof      
  Attaching frame to roof    
      The 2 metre long tubes were taken up one at a time and inserted into the manifold.  
  Close up of tubes and temp sensor  
    The collector consists of 20 heat pipe tubes, connected to a manifold at the top through which the water flows. This solar heated water then flows through the heat exchanger in the cylinder and back to the roof. The pump runs when the temp on the roof is 5 deg or more than the temp in the bottom of the cylinder. The temp sensor can be seen in the photo. The collector assembly is attached to the rafters at the 4 corners and the only holes in the tiles are two 15mm holes one at each end of the manifold.  
  Solar hot water cylinder

Click above for detailed view

  The solar Hot water cylinder is tall and thin compared to a standard one. This helps with the stratification of the water and it is quite common to have at least 30 deg Centigrade difference between the top and bottom in the morning. This is further helped by a baffle on the cold water input which stops the incoming water stirring up all the water in the cylinder.
It has 2 coils, one for the solar heating loop which is very close to the bottom of the cylinder and a coil for the existing gas powered boiler near the top. There are temperature sensors inside the cylinder at top and bottom, the bottom one is used to control when the solar pump works, the top one is for human interest as it lets me know how hot the water is in the top of the cylinder. These sensors are in pockets inside the cylinder not pressed against the outside for a more accurate reading.
The cylinder also has double the British Standard thickness of insulation (in 1999) around it to minimise any losses. In the picture you can also see a temp sensor near the top coil this is for the boiler thermostat.
  As the system is pressurised, the expansion vessel is needed because of the variation in pressure as the water heats up. Normal operating pressure is 0.75 Bar  
  Control board    
    The control board came pre-assembled from Solarsense (Swansea) and contains the pump, controller, non return valve Pressure gauge and a flow meter. This made installation very easy, and removed any risk of connecting things incorrectly. As you can see I installed it in the loft out of the way. It is directly above the hot water cylinder.
(All the pipes were lagged when installation completed.)