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How to Charge a Pressurized Solar Thermal System: Step 3
There are three steps to the charging process. Make sure you read and understand all three stages before starting the charging process.
Ground Mounts for Solar Collectors
Although almost all urban installations opt for roof-mounted arrays, ground mounting is a popular alternative because it is much more flexible. The biggest advantage is that the installation location can be chosen for optimum solar output rather than relying on which way the roof happens to point.
If you decide to ground-mount your collectors you should be aware of the following factors:
How to Charge a High-Mass Solar Thermal System
Charging a high-mass solar thermal heating system is much like charging a pressurized system. However, flushing all the air out is more complicated if you're running a combination system: you will need to flush each individual circuit. Always keep at least one circuit open during this procedure.
Mounting Heat Exchangers
In many cases, mounting the heat exchanger is one of the easiest parts of system installation, especially if you buy a pre-packaged kit; you just put the module on the storage tank and tighten a few unions. However, you may decide to construct your own heat exchanger from individual parts. In any case, the first step is to install the storage tank, then attach the exchanger.
AC Power and Controls in Solar Thermal Installations
All solar thermal systems need electric pumps to operate, except thermosiphon and ICS setups. However, you can't just plug the pump in and leave it running all the time. If you did, it would reverse the energy gathering process, dispersing stored heat through cold solar collectors into the night. The installation needs a control system to switch the pump on when there is heat to be gathered and off when there isn't.
Preparing for Plumbing
Good plumbing is a return on investment in itself. Proper plumbing, carefully planned and implemented with professional soldering and workmanship can last 100 years, so it's worth doing it right. If you're a newbie, you will want to either practice beforehand or employ a skilled professional.
Sensors for Solar Thermal Control Systems
There are many different sensors that work with solar thermal control systems, ranging from flat models which bolt onto equipment, to screw-in threaded models, to pointed models designed for immersion in liquids. Most consist of a ¼-inch diameter copper cylinder about an inch long, with two wires sticking out the end.
Solar Thermal Plumbing Toolkit
Before you start any serious plumbing work, make sure you have the right tools. Your system schematic (you did create one, didn't you?) will tell you how much piping you need, as well as all the fittings and other consumables required.
You will also need:
DC Power and Controls in Solar Thermal Installations
The main advantage of using DC power to run a solar thermal installation is that you can draw that power from a PV panel and, at the same time, eliminate the need for a controller.
Since PV-based power will only switch on when the sun shines, the solar thermal installation's pump will only run when there is heat to be gathered. When the sun disappears, both the PV power and the pump will switch off.