How much do you know about Solar Water Heaters?
With the rise in electricity costs, solar water heating has become the norm in many residential and commercial setups. There has been a rise in the sale of solar-related products. Concerns around the environment have driven green energy solutions to their highest in recent years. Solar water heating has become quite common in our urban areas, with people opting to lower their electricity costs.
We use most solar water heaters for domestic water heating purposes. They are a cost-effective system for providing your home with hot water. The major advantage of solar water systems is that we can use them in any climatic conditions so long as there are periods of sunlight which is a free natural resource.
How does a solar water heating system work?
Solar water heaters have a solar collector and a water storage tank.We have two types of solar water systems; active solar water heater and passive water solar heater. Active have circulating pumps and controls and passive water heaters don’t have.
Active solar water system
Under this category we have;
- Direct circulation system
The pumps circulate the water from the collectors to the household. They work very well in areas where the climate does not reach freezing levels.
- Indirect circulation system
The pumps installed transmit a non-freezing, heat-transferring fluid in the collectors and the heat exchanger. The water is heated and transferred back to the home. This is more common in areas where the temperatures can go below zero.
Passive water solar water system
They are usually less efficient, less expensive, and last longer compared to the active solar systems and hence more reliable. There are two types ofsystems under the passive water system;
- Integral collector-storage system
They are the best for household individuals who use a lot of heated water both at daytime and night-time. They are perfect for areas with no freezing temperatures and enjoy sunny days.
- Thermosyphon system
The warm water will rise, and cold water sinks when it flows through the system. The collector has to be installed under the water storage tank to facilitate the warm water to be on the top of the tank. This system is very reliable but more expensive to install. Care needs to be taken on the design of the roof of the house before the installation.
Solar collector and storage tanks
A good solar heater requires a well-insulated storage tank. Then the storage tank is installed with an additional connector for the inlet and outlet to the solar collector. We have a two-tank system and a one-tank system. In the two-tank system, the installed solar water heater will preheat the water before its transfer to the conventional water heater. The one-tank system will have a backup heater installed in the solar storage tank.
They use three types of collectors in a solar heating system;
- Evacuated-tube collector
This features transparent glass tubes with each having an outer tube with a metal absorber that is hooked up to a fin. These fins absorb solar energy and inhibit heat loss. The evacuated tube solar collector is usually for commercial purposes.
- Integral collector-storage system
This system features one or more black tubes in an insulated gauze box. Coldwater first flows through the solar collector preheating it and continues flowing through the conventional water heater to provide a more reliable source of hot water. They mostly install it in areas where pipes have the likelihood of freezing through cold weather.
- Flat-plate collector
There are two types of collectors, the glazed plate collector that are insulated and weatherproof, and the unglazed plate collector that have a dark absorber metal and polymer plate with no covering. The Unglazed plate collector are mostly used for pool heating.
What to do when selecting a solar water heating system
One needs to understand what they need to do before deciding to purchase a solar water heating system.
You will need to do the following;
- Estimate the energy efficiency of a solar system vis-Ă -vis using convectional electricity heating.
- Evaluate your solar resource. The period of sunlight you enjoy during the day.
- Determine the correct system for your household or commercial needs
- Investigate local building codes for the installation of the solar system.
