DSHW Installation in Dominica 2004

    


Last year, load analysis was conducted for the Springfield plantation, with the results expressed the need to reduce energy costs when heating water at the main guesthouse. The decision to install a direct open-loop system instead of a thermosiphon was decided on due to the fact that water tank could not be placed upon the roof above the solar collectors. A closed-loop system was deemed not applicable due to the tropical climate and lack of freezing conditions.
   Upon arrival to Dominica, our first task was to repair/rebuild the solar collectors to be placed on the roof. This involved the cutting and glazing material, riveting, caulking of glazing and the copper layer separating the insulation from the rest of the collector. Minor repairs were also needed on the cold supply and hot output pipes of the collectors.

                   
After these repairs were completed, brackets were mounted on collectors, they were pressures tested for leaks, and transported down to the guesthouse with David’s truck. 2x4s were painted green to match the lush landscape of the plantation. Next, these were mounted to the joists on the roof, with lag bolts and nuts that needed to be purchased at the local hardware store (a long story that won’t be told here J).
At first, the plan was to install two-tank system, one relying solely on solar heating, the other to be used as an electrical backup. Unfortunately, due to some technical difficulties, one tank was damaged which made it no longer useable in the system. Modifications to the original two-tank design enabled us to continue installation with only one tank.


All of the hot water pipes in the guesthouse were insulated with black foam to maintain high temperatures and to reduce heat loss between the hot water heater and the faucet. After the solar were installed on top if the roof, our work was then focused inside on the hot water tank and the plumbing needed to connect the tank to the collectors. We made sure that the DC pump was installed correctly, so the water was pumped in the proper direction. A check valve was also installed, but later removed when we realized it was installed incorrectly. Although this was removed, the system will still function properly since this was only a precautionary measure to ensure that reverse flow would not occur.
Currently, the solar hot water heater is up and running; the solar collectors are heating the water during the day and pumping to the hot water tank for storage and eventually out to individual faucets and showers. By installing this system, we should save the guesthouse about 35% of the monthly electrical bill; therefore within one year the system should pay for itself.