Pressurized Solar Thermal System Pros and Cons
These systems have many advantages:
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Pressurized Solar Thermal System Thermosiphoning
Pressurized solar hot water installations have a closed solar fluid loop that is always full of liquid. If the collectors get colder than the storage tank and are situated above the tank (as is usually the case), thermosiphoning can occur.
Pressure Concerns in Pressurized Solar Thermal Systems
As the name suggests, a pressurized solar thermal system operates under pressure. In particular, the solar fluid circuit is always under a certain amount of pressure, which can vary enormously depending on the local climate and a variety of other factors. It is vital to understand the effects of pressure and how the system is managed to avoid catastrophic events.
Drainback Solar Thermal System Heat Exchangers
Like any closed-loop installation, drainback solar hot water systems use a heat exchanger to pass energy from the solar fluid to the domestic water supply. However, drainback setups include a third, specialized tank – the drainback tank – which holds all the solar fluid when the system is idle. This fluid can still be very hot when circulation stops, so it makes sense to have a means of passing that energy to the domestic supply rather than waste it.
Integral Collector Storage Solar Thermal System Layout
Integral collector storage (ICS) solar hot water systems are remarkably simple and cheap when compared to the other types. They don't use pumps, they don't need controllers, they use only one tank and they require very few extra components beyond a big water tank, some pipes and a pile of insulation materials.
Solar Thermal System Check Valves
A check valve is a simple device that only allows liquids to flow through it in one direction. These valves have an arrow marked on the outside to show the allowed flow direction. Two different types are used in solar thermal installations: "spring" and "swing" check valves.
Maintenance of Solar PV Modules
Eliminate Tree Shading
You will want to shade your house's south side from the summer sun, but not your PV array. Even partial shading can cause a disproportionate loss in electrical energy. Trees should be maintained to prevent obstruction, especially between 9 a.m. and 3 p.m. (the prime sunlight hours).
Solar Thermal Equipment: Vents and Vacuum Breakers
All modern solar thermal systems use both vents and vacuum breakers. Vents are used to allow air to escape from a circuit that holds fluid and vacuum breakers do the opposite, letting air in when the internal pressure falls too low.
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