With the rapid increase of price of the non-renewable energy sources like natural gas, coal and petroleum, the demand of sun water heaters have risen. Being renewable and widely available energy at the same time, these heating systems are utilized in even the remotest corners of the earth. Residential, industrial and various institutional sectors have adopted the SWH system to convert the thermal energy into heat energy through direct heating or through the light concentrating mirrors. These systems are either installed on the rooftop or on the wall or anywhere outdoor with a storage tank.
The Accessories Used In SWH
The three main components of the solar water heating system or SWH include the thermal panel or solar panel installed on rooftop, the storage tank for hot water and the circulating pump that transfers the energy of sunlight to the storage tank from the collector.
The DC Pump and the solar water heater panels (PV panels) are matched properly to elongate and enhance pump performance. They are easy to install and come at low maintenance with grid-power system. The solar geyser pump or bubble pump separates bubbles from hot water, so that the water is heated under low temperature.
In order to reduce heat loss the storage tanks are placed either obscured from view or in conditioned/semi-conditioned place or below the collectors. The Insulated tanks come topped with glass cover so that radiation and convection is reduced and they are insulated thermally.
The differential controller keeps track of the difference of water temperature between collector and storage tank. The controller ensures zero operation of solar water geyser when the water is not sufficiently warm. It starts pump only when the water of collector is 8 to 10-degree warmer than tank water. As soon as the difference is 3 to 5-degree, the pump stops.
Function of Solar Water Heater
The solar water heater is efficient in heating around 50-70% water used in bathroom or kitchen, which is why they are gradually taking over the conventional energy sources. With the collector on rooftop, the light energy of the sun is converted into heat energy which is then transferred to the storage tank through circulating pump. As the collector becomes hotter than stored water in the tank, the thermal regulator triggers exchange of water and prevents the pumps from utilizing electricity unnecessarily i.e. prevents it from overheating.
Efficiency of the water heater
During the summertime midday, under the direct exposure of the sun in a cloudless sky, the solar water heater works with maximum efficiency, especially when the solar collectors face south. The efficient heaters even work in cloudy days for significant period of the day. They work great even while facing east and west however most effectiveness is achieved when the collectors are installed at 25-degree with the horizon , They also work great if installed vertically on the façade.
In case of overcast sky or in low light conditions, the pre-heated water is run through backup system that brings water under required temperature. With no emission of Carbon dioxide, the whole system ensures water heating at constant temperature.
How Solar Heaters Work
With variegated storage tank, collector and mechanism, the solar water heater price varies, so does the utility. Below is the utility of heaters according to their collector types –
Batch Collector –Known as the ICS or Integrated Collector Storage, the water is heated within the insulated box or dark tanks and is kept heated for long hours. The tap is prevented from scalding with the tampering valve. In frozen regions, these collectors are not so effective.
Flat-Plate Collector –On flat absorbing plates, the copper tubes are connected with two pipes on two manifolds in a parallel way. This solar water heater for home has the plate reinforced by tempered glass and tucked inside insulated box. Around 50% hot water requirement is addressed by this heater that has the capacity of 40 gallons generally.
Evacuated Tube Collector –Water is run through the thermos-like metal or glass tube that is again surrounded by a larger tube to ensure minimum heat loss. As they are suitable even for those regions having temperature of -40-degree centigrade and during cloudy weather, they are the best solar water heater. However, their cost is expensive than Flat-Plate.
Circulation System in Solar Water Heaters
The Direct Circulation System is suitable for the places that hardly get freezing temperature and water is circulated through the solar collectors. The Indirect or Closed Loop System is perfect for freezing climate where heat is transferred with non-freezing fluid to the storage tank containing water. The Forced Circulation or Active Systems circulate water between collector and tank through pumps, controllers and valves. On the solar water heater price list, you will also find the passive systems which are less expensive as they apply natural convection rather than pumps to transfer water to tanks.
Cost Of Water Heaters
The installation process of the water heaters are the most vital factors as it often takes 2-4 days for full installation. Regarding the size, circulation system, collector types and quality, the price tag varies. As a matter of fact, the price in cold regions will be more than in warmer regions as the system is complex and need more time to install. The solar water heater cost for maintenance is another important part for your budget however in most cases, the maintenance cost is insignificant. In colder regions, the maintenance cost will be expensive.