Home » Solar Panels » Solar Thermal Panels for Water Heating

The cost of basic utilities such as electric or gas heating and cooling is almost unavoidable. Most of us simply sign up with a local utility company and pay for what we use without ever wondering if there is a better way to go about getting these basic comforts for ourselves. Consider the hot water in your home. This is something that most developed countries take for granted. But do you ever think about how it gets there and what it is costing you?


The average hot water system consists of a tank which forces heat and stores a set amount of water. Whenever you turn on a tap in your house to use the hot water, it is then sent up from this tank. The method in which the water is heated generally relies on gas or electric power. This obviously adds to the corresponding utility bill. Since hot water is used in the average home pretty much every day one can expect that the energy consumed in creating hot water tends to be a major factor in the size of the utility bill at the end of the month. Considering how frequently this is used, many homeowners wonder if there is a way to reduce the cost of heating their water. In fact, there is.


Electricity and gas have been harnessed for decades to give us energy for many purposes throughout the home including heating water, powering ovens, and giving us light. However, there are several other energy sources that Earth has made available which we are starting to learn how to properly harness. Solar power is one such energy source. You surely are aware of solar panels that can provide electricity to cars, lights, and even the power grid itself. These types of solar panels called photovoltaic or PV panels. They take the energy from sunlight and convert it into electricity through the power of physics. To learn more about how PV creates electricity, check out this LiveScience article. If you have enough PV panels you may be able to replace your electric consumption from grid power with your own solar power. In many locations, however, governmental regulations do not allow this since electricity is a strictly governed utility. If you are looking to take advantage of the sun to reduce your energy consumption then it may be achievable in other, legal ways.


The sun can also be used for non-electric energy purposes. The easiest way to harness energy from the sun is by capturing and transferring thermal energy. This can be done by simply taking advantage of the heat that the sun provides through both basic thermal exchange, as well as converting light energy into heat. Greenhouses are an obvious example of how the sun’s light can be transformed into heat that can be used for many purposes through a simple passive process. While the sun’s energy can be used by PV panels to electrically heat water, it can also be used by thermal panels to heat water for residential use.


A solar thermal panel is the major component of an overall solar water heater system, but there are several other parts of the complete system. In the same way that a traditional water heating system requires a storage tank, so too does a solar heating system. This is because the climate and sun availability is not a constant resource, so heated water cannot be relied upon on an on-demand basis from this solar water heater system and will need to be stored. The water in the tank is heated by fluid the run through the solar thermal panel to collect the sun’s heat and then bring it to the storage tank. The whole system is kept in motion by a pump that can either be run electronically or through a solar photovoltaic cell.


The real powerhouse of a solar thermal water heating system is the thermal panel Itself. These panels tend to be one of two major designs. Both of these designs are designed with the intent of capturing the heat provided by the sun as well as to capture the sun’s light and convert it into heat energy. This heat is then transferred to water or another thermal liquid that is carried down to the water tank where the heat is again transferred, this time to the actual water that is used in the home. Finally, the cooled system liquid is pumped back up to the thermal panel in order to be heated once more.

There are several designs of solar thermal panels that can be used in a water heating system. The most simple to understand is the flat plate collector panel. This type of solar panel runs pipes through a flat box that has a thick glass top. The top allows light in but traps the resulting heat so that the box heats up much like an oven. Therefore, when liquid runs through a set of pipes within the box it is heated and can carry this heat to the water tank.


Another common type of solar thermal panel is the evacuated tube panel. An evacuated tube is an empty tube that traps the light from the sun and converts it into heat in the same way that a greenhouse would. A full panel is made up of many of these evacuated tubes. Each tube is connected at the top to a medium through which the system liquid flows in order to transfer the heat that has been captured in the tube. In some cases, each tube has its own internal liquid system that is heated up in order to aid the transfer of heat from the inside of the tube to the system liquid that is running through the heat transfer system. It is almost like the same process that brings the heat from the solar thermal panel to the hot water tank is being repeated on a smaller level within the panel at each tube. This can be a bit tricky to visualize so here is a good breakdown of the design of this type of panel.

If you are considering using solar thermal panels to supplement your water heating needs, either of these designs is a good place to start regardless of budget. All you need is a nice sunny spot and the proper installation and you will be harvesting the sun’s rays to your own advantage in no time.