Solar hot water systems

What are solar hot water systems?

Solar hot water systems are systems that can heat water for homes and even swimming pools. These systems can also be fitted in industries for industrial purposes like distillation, sterilization and disinfection etc. usually a solar collector is placed on top of a box, below which water is either passively flowing, or actively pumped. The solar absorber can be simple sheet metal (like copper) or evacuated tubing. PV panels can also be used to create thermal energy to heat the water. Most homes have these hot water systems installed on their roofs next to their water storage tanks, and some people even use them to heat water in their swimming pools.
Advantages of solar hot water systems:

These systems can help save tremendously on electricity bills. Heating water can cause your electricity bill to rise very high, and solar powered water heating systems not only reduce your electricity costs, but also help conserve the environment.

How solar hot water works

Apart from the initial investment that goes into the purchase and installation, of solar hot water systems, the optimum functionality and durability of solar hot water systems is incomparable to traditional means like electric water heaters. These systems are extremely useful, convenient and have been designed to give excellent results.

Types of collectors used in solar hot water systems:

Mainly, two kinds of collectors are used in the mechanism of a solar hot water system which have been enlisted and described as follows:

• flat plate collectors (suitable where tank roof mounting is required)

• evacuated tubes (more efficient and great for frost prone areas)

Flat plate solar collectors

The mechanism of flat plate collectors is such that they function on copper pipes that run through a specialized collector which is completely covered with glass and is sometimes attached or connected to a water tank generally placed on the roof. With the help of this mechanism and set up, the water thermo-siphons inside and out of the tank itself, and this in turn causes the water to become heated. There are a huge variety of flat plate collector systems available. These systems are less efficient than evacuated tube solar collectors.
Evacuated tube solar collectors

The mechanism of evacuated tubes is rather different. These function with a vacuum filled glass tube within and copper pipes running through the middle. All these pipes are connected to a specific manifold which is then connected to slow flow circulatory pump. This circulatory pump is used for pumping water to a water storage tank usually placed below. This allows the water to become heated during the day time. Because the tank is insulated, this water remains heated and can be used even during the night and the next day.

This system is generally preferred over the former for a number of reasons, mainly because they do not require direct sun light to heat the water. They have the ability to use air on a humid day to perform the required function. The vacuum contained inside the glass tube enhances the overall efficiency and effectiveness of the system. This means that even when the sun is not at an optimum angle, there is no difference in the functionality of the evacuated tube system.

Evacuated tube vs. flat panel – which is more efficient?

It is a proven fact that the evacuated tube system is more efficient and the durability is greater too. It is also more economical because its damage repair is relatively cheaper than the former, in case of damages to the system.
The water tank and thermal mixing

When the temperature increases, the heated water transferred to the tank by the solar collector is drawn from the top portion for household usage.

There are chances that the temperature of this water may exceed 60 degrees. This is a measure that is required for complete sanitization, as this is optimum temperature for eliminating bacteria. This means that that the water that comes out from the taps for household use is completely clean. The system has a tempering valve with which the temperature of the water can be adjusted as required.
Hot water and household energy usage.

Water heating systems that run on gas or electricity are responsible for nearly 20% of green house gas emissions. This means that by simply replacing your conventional gas or electrical water heating systems and investing in solar heating systems has countless benefits for you, and for the environment. Not only are you using a renewable means of generating heat energy, which is the sun, but you are also conserving fossil fuels and reducing the carbon emission damage that man has drastically done to our environment over the course of the previous two centuries. Many companies are now offering discounted rates on solar water heating systems in order to encourage people to switch to the more eco-friendly option. Installing PV panels for electricity generation and solar powered hot water systems can help you contribute your bit for the Earth, and also helps cut down your water heating and electricity expenses significantly!