Adveco Solar Thermal Collectors
As with any technology, issues can arise if a commercial system is poorly designed or maintained. In terms of solar thermal systems, the results can vary from frustrating to catastrophic and can prove to be extremely costly.
A standard solar system will consist of solar collector(s), pump, storage tank, heat exchanger, expansion vessel and a set of sensors and controllers. The system also contains Solar Fluid.
By far the greater concern is stagnation of the Solar Fluid as a result of high temperature build-up within the collectors when a system is not operating.
If a solar thermal system has no overheat protection the fluid can change to the consistency of tar. The ‘tar’ can rapidly develop as a film, and within a multiple collector system it is likely that some of these will become blocked and will not be able to be cleared out causing permanent damage and resulting in very high repair costs. We have seen this issue develop in systems a matter of weeks after initial installation!
Overheat protection is therefore vitally important and will typically require the addition of a large solar storage or buffer vessels to dump unwanted heat to stop the system stagnating. Together with the heat dump system starting in the middle of the day due to a short period of low demand, the Solar Thermal application could be extremely inefficient.
At Adveco, we are proponents of systems that offer drain back, which as the name implies drains the Solar Fluid from the collector to a reservoir when not in use, allowing for a system to be safely off.
A drain back vessel located in the plant room is one option, that will also allow for pipework fluid, but will require greater head pumps.
With Adveco's flat plate collectors, featuring integrated drain back module, commercial buildings with high demands can deploy a large number of collectors with a small tank and still provide high temperature water with the knowledge that in times of low use high temperature build up in collectors is impossible. Thi ensure the system remains protected. This approach is also more cost effective as there is no requirement for installation of large solar storage, and more efficient as there is no call to dump unused heat.