Indoor swimming pools have exactly the same heat load throughout the year. A solar thermal setup can provide 50% of the load in winter and 100% in summer – the amount varies because there's less solar radiation in winter to generate heat. In general, an indoor pool solar thermal installation is sized to generate the right amount of heat on the best possible day: this ensures that the system never overheats.
A pressurized system should really be referred to as a "closed-loop pressurized antifreeze solar thermal system" – the two-word version is much simpler and more common! Pressurized systems are the most flexible type of solar hot water installation and, consequently, are the most common worldwide.
Much like seasonal swimming pools, spas and hot tubs can profit enormously from solar heating systems. This is especially true if you're installing a solar thermal system for your domestic hot water supply or space heating because the tub or spa can act as a shunt load, using excess output from the household system.
A pressurized solar hot water system almost always follows a standard layout, which is one of the reasons most manufacturers are able to offer simplified kits for residential installations.
In most parts of the world, space heating systems are installed in every home. They provide warmth and comfort during the colder part of the year. Unfortunately, the vast majority of these systems rely on grid-tied, non-renewable power sources to provide that heat. In a bid to reduce our environmental impact – not to mention our operating costs – we can use the sun's power to provide space heating.
If you think a pressurized solar hot water system fits your needs, you must consider a variety of rules, limitations and requirements, as outlined below.
Collector arrays should be mounted so that there's a slight slope towards the return inlet, where the solar fluid enters, which should also have a drain for maintenance.
Like solar thermal hot water installations, there are many different options available for space heating. Before you consider them and work out which is best for you, it is important to be aware of the limitations and pre-installation suggestions outlined below.
These systems have many advantages:
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.
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.
