Solar Water Heater comprises of an array of solar collectors to collect solar energy and an insulated tank to store hot water. Both are connected to each other. During the day time, water in solar collectors gets heated which is either pumped or flown automatically on thermo-siphon principle to the storage tank. Direct systems circulate water through solar collectors where it is heated by the sun. The heated water is then stored in a tank, sent to a tank less water heater, or used directly. These systems are preferable in climates where it rarely freezes. The sun’s thermal energy heats the fluid in the solar collectors.
Solar water heater is a system that utilizes solar energy (or the energy from sunlight) to heat water. The system is not connected to electricity supply and thus does not have an on-off switch, but it uses the sunlight throughout the day to heat the water and store it in the storage tank.
Solar water heater system, during winter, can be effective because of efficient insulation. When the temperature is cold during winters, radiator fluid technology is used in solar water heaters. The heat exchange tank exchanges the heat of the fluid with water and warms the water in the storage tank.
HOW HOT CAN A SOLAR WATER HEATER BE?
Water heated by the sun can reach temperatures exceeding 212° F, but the normal temperature for household use is only 120°F to 130° F. Solar energy can easily achieve these temperatures, even on cloudy days.
Since solar energy systems require sunlight, the bulk of production will take place under sunny conditions. A system can generate 50-70% of its typical output under bright overcast conditions. When rain or excessive days of cloudy conditions exist, the auxiliary backup will use conventional energy to heat water.
WHAT IS THE WORKING PRINCIPLE OF SOLAR WATER HEATER?
The energy emitted by sun, the sun’s rays, is made of heat and sunlight. Both can be captured, transformed and used in your home to heat water. A thermosiphon solar water heater is composed of a tank (accumulator) and a solar collector which is connected to the tank.
DIFFERENT TYPES OF SOLAR WATER HEATERS
There are five types of solar hot water systems:
- Thermosiphon Systems. These systems heat water or an antifreeze fluid, such as glycol.
- Direct-Circulation Systems. These systems pump water from storage to collectors during sunny hours.
- Drain-Down Systems.
- Indirect Water-Heating Systems.
- Air Systems.
HOW EFFICIENT ARE SOLAR WATER HEATERS?
Solar thermal systems convert 60 percent to 70 percent of the sun’s energy into heat, while high-end photovoltaics top out at around 24 percent efficiency. … Because heating it accounts for 25 percent to 30 percent of the average home’s energy use, a solar water heater can make a sizable dent in the utility bill.
DOES SOLAR HOT WATER SAVE?
Solar water heating systems usually cost more to purchase and install than conventional water heating systems. However, a solar water heater can usually save you money in the long run. How much money you save depends on the following: The amount of hot water you use.
IS LEAKING WATER HEATER DANGEROUS?
While this problem is easy to fix it is the most concerning and dangerous because a significant amount of excess pressure within your tank will cause the T&P Valve to release scalding hot steam and water. Located near the bottom of your tank, the drain valve can leak due to use and deterioration overtime.
BENEFITS OF SOLAR HOT WATER
While a solar water heater won’t directly reduce your water consumption, it does carry with it many benefits. Few are listed below:
- Fighting climate change.
Water heating accounts for 17 percent of a typical home’s energy use. Many North American homes heat water with natural gas or other fossil fuels. That’s many tons of carbon going into the atmosphere. Switching to solar hot water is a great way to reduce carbon and other greenhouse emissions and protect our climate.
- Protecting water quality.
Carbon and particulates aren’t the only byproducts of burning fossil fuel. The Natural Resources Defense Council has identified power plants as the primary source of mercury and other toxic heavy metals being released into the environment each year. These substances are a major threat to the health of our rivers, streams and lakes — and to human health as well. Solar water heating is one practical step we can take to put a stop to mercury contamination of our watersheds.
- Monthly savings.
A solar water heater can provide up to 80 percent of your hot water needs, even in temperate climates. This translates to major utility bill savings, month after month. In fact, a solar hot water system typically pays for itself in just four to eight years, and can be expected to last for 40 years or more. That’s a lot of free energy, and a lot of savings.
- Increased home value.
Studies show that homes with solar sell faster and at higher prices than those without. Thus, adding solar hot water to your home is an investment that will pay back whether you stay or sell.
COMMON PROBLEMS AND HOW TO TELL WHEN SERVICING IS REQUIRED
Solar water heater systems are an efficient and cost-effective manner to provide a continual supply of hot water to homes. These systems operate by collecting the sun’s energy through panels that are positioned appropriately on your roof or another location on your property. Today, these heating systems have become more reliable and durable than their early counterparts were in operation, but this does not mean that problems do not occur with them on occasion. We list some of the common problems below and offer advice on how to tell when servicing is necessary to solve them.
Leaking can occur if there is damage to the pressure-relief or temperature valve, either of which is in the solar panels on the roof. Another reason for leaks is if the fittings on pipes work loose or if the pipes break for some reason.
No Hot Water
If you discover that there is no hot water at all, it could be your mixing valve, auxiliary heater, thermostat, or gas or electric heating element causing this issue. Whatever the cause, you may need to replace the part to once again have hot water.
Water Is Not Sufficiently Hot
Another issue that could occur with a solar water heater system is that the water is not sufficiently hot for your needs. One reason for this could be too many cloudy days in a row make is difficult for the solar panels to convert the right amount of energy to heat your water up to the desired temperature. Also, your panels not being in the right position is yet an additional reason for this to occur.
Loose Connections and Wiring
You should keep your solar water heater system in the proper condition 24/7, and this includes the connections and wiring. Regular inspections will ensure that these elements do not loosen to the point of malfunction. At the same time, you should check for any frayed wires since they can be a fire hazard.
Circulation Pump Issues
Problems with the circulation pump can prevent the efficient delivery of hot water. Either the pump can malfunction or there can be a blockage in the circulation system.
Broken Solar Panels
At times, the glass on the solar panels can break due to weather or even just age. This break can negatively affect a panel’s ability to collect energy from the sun.
THE BENEFITS OF SOLAR HEATING
- Endless amounts of energy, free of charge
- No CO2 emissions during operation
- Cost savings: up to 60% less energy to heat water, up to 35% less energy for space heating
- Reduced consumption of fossil fuels
- Solar thermal systems can be integrated into existing systems
- Modern systems work efficiently even in winter
HOW SOLAR HEATER WORKS
Solar thermal works in principle like a dark garden hose lying in the sun. The surface of the hose absorbs the sunlight and in particular the heat radiation so that the water therein is heated. Solar heating works in the following steps:
- The collectors absorb the sunlight via the absorber. Here, a special heat carrier fluid is heated up.
- A pump transports the fluid to the heat exchanger of the solar storage.
- There, the thermal energy is transmitted to a storage tank.
- Should the solar radiation be insufficient to heat up the water, a conventional heating system will heat up the storage tank to the desired set temperature.
A solar thermal system supplies depending on the design annual average approximately 60% of the necessary energy to meet the hot water needs.
WHAT IS A SOLAR COLLECTOR AND HOW DOES IT WORK?
The inside of the solar collector is usually evacuated, the energy contained within the solar collect is basically trapped and thus heats the coolant contained within the tubes. The tubes are usually made from copper, and the back plate is painted black to help absorb solar radiation.
Flat plate solar thermal systems
Is another common type of solar collector which has been in use since the 1950s. The main components of a flat plate panel are a dark colored flat plate absorber with an insulated cover, a heat transferring liquid containing antifreeze to transfer heat from the absorber to the water tank, and an insulated backing. The flat plate feature of the solar panel increases the surface area for heat absorption. The heat transfer liquid is circulated through copper or silicon tubes contained within the flat surface plate.
Thermodynamic solar panels are a new development in solar thermal technology. They are closely related to air source heat pumps in their design but are deployed on the roof or walls like regular solar thermal panels and do not have to be south facing. The concept behind thermodynamic solar technology is that it acts like a reverse freezer and they differ from conventional solar thermal in that they do not use solar radiation to heat up heat transferring liquids.
Solar thermal air collectors
Solar air heaters are mostly used for space heating and can be both glazed and unglazed. They are among the most efficient and economical solar thermal technologies available and are mostly used in the commercial sector. The top sheet of a glazed system has a transparent top layer and an insulated surrounding frame and back panel to prevent heat loss to the surrounding air.
Flat Plate Collectors
These collectors consist of airtight boxes with a glass, or other transparent material cover. There are several designs on the arrangement of the internal tubing of flat plate collectors
Solar thermal heat storage
A thermal heat store will be necessary to retain the heat generated by a solar thermal installation unit until the heat is ready to be used. Thermal heat stores also work particularly well in conjunction with solar thermal panels. The main storage option in a domestic setting would be a large insulated cylinder that contains copper coils or plate heat exchangers. The system can also include a heating element like an immersion heater. A thermal storage unit can utilize a number of different and combined technologies for hot water generation and space heating.