Most of the year we have to spend money on heating their homes. In this situation, any help would be superfluous. Solar energy is suitable for this purpose as well as possible: absolutely clean and free.
Modern technologies allow solar heating private houses, not only in the southern regions, but also in the conditions of the middle band.
The content of the article:
- That can offer modern technology
- Pros and cons of using solar energy
- Open solar collectors
- Tubular solar collectors
- Advantages and disadvantages of tubular collectors
- Closed flat solar collectors
- Comparison of characteristics of solar collectors
- Ways of Connecting to the heating system
- The circuit connecting the heat reservoir
- Wiring diagram of the solar battery
- How to calculate the required capacity of the reservoir
- Useful videos on the topic
That can offer modern technology
The average of 1 m2 of surface land 161 receives solar energy W per hour. Of course, at the equator, this figure is many times higher than in the Arctic. In addition, the density of solar radiation depends on the time of year.
In the Moscow region the intensity of solar radiation in December and January is different from the May and July more than five times. However, the current system is so effective that they are able to operate virtually everywhere on earth.
Task utilization of solar radiation energy with maximum efficiency is achieved in two ways: direct heating of a thermal solar collectors and photovoltaic batteries.
Solar cells convert the energy of the beginning of sunlight into electricity, then pass through a special system to consumers, such as electric boiler.
Thermal reservoirs being heated by solar rays heated coolant heating and hot water systems.
Thermal collectors come in several forms, including open and closed systems, flat and spherical structure, hemispherical hubs collectors and many other options.
The thermal energy obtained from solar collectors used for heating hot water or heating fluid.
Despite the apparent progress in the development of collecting solutions, accumulation and use of solar energy, there are advantages and disadvantages.
Pros and cons of using solar energy
The most obvious advantage of using solar energy is its accessibility. In fact, even in the gloomy and cloudy weather, solar energy can be collected and used.
The second plus - a zero emissions. In fact, it is the most environmentally friendly form of energy and natural. Solar panels and collectors do not produce noise. In most cases, they are mounted on the roofs of buildings, without taking valuable suburban land area.
Disadvantages associated with the use of solar energy, are to inconstancy illumination. At night, it becomes nothing to collect, the situation is compounded by the fact that the peak of the heating season is the most short light days of the year.
It is necessary to monitor the purity of the optical panel, minor contamination drastically reduces efficiency.
In addition, we can not say that the operation of the system on solar energy cost is completely free, there are fixed costs of equipment depreciation, circulation pump and control electronics.
Open solar collectors
Outdoor solar collector is unprotected from external influences tubing system which circulates heated heat transfer fluid directly to the sun. As the coolant, water is used, gas, air, antifreeze. Tube or fixed to the support plate in the form of a coil, or joined in parallel rows to the outlet nozzle.
We open collectors usually do not have any insulation. The design is very simple, so it is inexpensive and is often made independently.
Due to the lack of insulation virtually stores the energy from the sun, have a low efficiency. Used them mostly in the summer to heat water in swimming pools or summer shower. Installed in sunny and warm regions, with small changes in temperature of the ambient air and heated water. Only work well in sunny, calm weather.
Tubular solar collectors
The tubular solar collectors are assembled from individual pipes, which runs the water, gas or vapor. This is a type of solar plants open. However, the coolant is already much better protected from the external negativity. Especially in vacuum systems, arranged according to the principle of thermoses.
Each tube is connected to the system separately, in parallel with each other. When failure of one tube it is easy to change to a new one. The whole structure can be assembled directly on the roof of the building, which greatly facilitates installation.
Plus a strong tubular solar collectors is in a cylindrical form the basic elements that make solar radiation captured all the daylight hours without the use of expensive tracking systems for the movement luminaries.
According to their construction tubes pen and coaxial solar collectors.
Coaxial pipe is a vessel or Dayura the familiar thermos. Made of two flasks between them evacuated. The inner surface of the inner core coated with a highly selective coating effectively absorbing solar energy.
Thermal energy from the inner tube of the selective layer of heat transferred from the indoor heat exchanger or aluminum plates. At this stage, undesirable heat losses occur.
Fountain tube is a glass cylinder with the inserted inside the pen absorber.
For a good insulation of the evacuated tube. Heat transfer from the absorber takes place without losses, so the efficiency of fountain tubes above.
By heat transfer method has two systems: the direct flow and Heat-(heat pipe).
It represents Heat-sealed container with a volatile liquid.
Inside Heat-volatile liquid it is that receives heat from the interior wall of the flask or by pen absorber. Under the influence of the temperature of the liquid boils and the vapor rises. After the heat given to the coolant heating or hot water, the steam condenses into the liquid and flows down.
As a volatile liquid, water is used frequently at a low pressure.
The co-current system uses U-shaped tube through which the coolant circulates water or heating systems.
One half of the U-shaped tube is designed for cold coolant, removes the second heated. When heated coolant expands and enters the tank, providing a natural circulation. As is the case with Heat-systems, the minimum angle of inclination should be at least 20⁰.
Once-through systems are more efficient since once heated coolant.
If the solar collector system is planned to be used all year round, then they injected a special antifreeze.
Advantages and disadvantages of tubular collectors
The use of tubular solar collectors has a number of advantages and disadvantages. The design of the tubular solar collector consists of identical elements which are relatively easy to replace.
Advantages:
- low heat loss;
- ability to operate at temperatures up -30⁰S;
- effective performance throughout the daylight hours;
- good performance in regions with temperate and cold climates;
- Low windage, sound systems ability to pass through the tubular air mass itself;
- possibility to manufacture a high coolant temperature.
Structurally, the tubular structure has a limited aperture surface. It has the following disadvantages:
- It is not capable of self-cleaning of snow, ice, frost;
- high price.
Despite the initial high cost, tube collectors quickly recouped. Have a long service life.
Closed flat solar collectors
Flat collector consists of an aluminum frame, special absorbent layer - absorber, a transparent coating, and pipe insulation.
As an absorber use blackened copper sheet, is ideally for creating geliosistem conductivity. When the absorption of solar energy absorber is transmitted solar energy received that coolant circulating through the tubes adjacent to the absorber system.
On the outer side of the closed panel is protected by a transparent coating. It is made of impact-resistant tempered glass having a transmission band 0,4-1,8mkm. At this range to the maximum of solar radiation. Shockproof glass is a good protection against hail. On the back of the whole panel is securely insulated.
The list of advantages of closed flat panels including:
- simple structure;
- good performance in regions with warm climates;
- possibility of installation at any angle in the presence of devices for changing the inclination angle;
- the ability to self-clean from snow and frost;
- low price.
Flat solar collectors are particularly advantageous, if their use is planned at the design stage. Service life in high-quality products is 50 years.
The disadvantages are:
- the high heat loss;
- a lot of weight;
- High wind resistance at the location of the panels at an angle to the horizon;
- limitations in performance with changes in temperature over 40 ° C.
Scope closed reservoirs is much wider than the open type solar units. In summer, they can fully meet the need for hot water. On colder days, the utilities are not included in the heating period, they can work instead of gas and electric heaters.
Comparison of characteristics of solar collectors
The most important indicator is the efficiency of the solar collector. Useful performance of different constructions of solar collectors is dependent on the temperature difference. In this flat collectors significantly less tubular.
When choosing a solar collector should pay attention to a number of parameters reflecting the efficiency and capacity of the device.
There are several important characteristics for solar collectors:
- adsorption coefficient - indicates the ratio to the total energy absorbed;
- emission coefficient - is the ratio of energy transmitted to the absorbed;
- and the total aperture area;
- Efficiency.
Aperture area - this is a working solar collector area. In flat-plate collector aperture area is maximized. The aperture area is the absorber area.
Ways of Connecting to the heating system
Since solar energy devices can not provide a stable energy supply and disabled, a system resistant to these deficiencies.
For central Russia solar devices can not ensure stable flow of energy, and therefore are used as additional system. Integration into the existing heating system and hot water for the different solar collector and solar batteries.
The circuit connecting the heat reservoir
Depending on the purpose of use of the heat collector to connect different systems are used. May be several:
- Summer version for hot water
- Winter version for heating and hot water supply
Summer most simple embodiment and may even cost without circulating pump, using a natural water circulation.
Water is heated in the solar collector and due to thermal expansion is supplied in the storage tank or boiler. Thus there is a natural circulation: in place of the hot water tank is sucked cold.
Like any system based on the natural circulation it does not work very efficiently, requiring compliance with the required slope. In addition, the buffer tank should be higher than the solar collector.
To keep the water as long as possible the hot tub should be thoroughly warmed.
If you really want to achieve the most efficient operation of a solar collector, wiring diagram complicated.
According to the solar collector system nonfreezing coolant circulates. It provides forced circulation pump under control of the controller.
The controller controls the operation of the circulation pump based on the testimony of at least two temperature sensors. The first sensor measures the temperature in the storage tank, the second - on the pipe supplying hot coolant solar collector. Once the temperature in the tank exceeds the temperature of the coolant in the reservoir controller disables the pump, stopping the circulation of the coolant through the system.
In turn, when the temperature in the storage tank below the boiler is switched predetermined.
Wiring diagram of the solar battery
It would be tempting to apply a similar scheme of solar power, is how it is implemented in the case of a solar collector, accumulating Received energy per day. Unfortunately the battery pack to create sufficient capacity is very expensive for the private home power supply system. Therefore, the connection scheme is as follows.
With the solar panels charge supplied to the charge controller that performs several functions: it provides a permanent charging of the batteries and the voltage stabilizes. Next, an electric current is supplied to the inverter, where the conversion constant 12V or 24V DC into 220V AC single phase.
Unfortunately, our electrical not adapted to obtain energy can only operate in one direction from the source to the consumer. For this reason, you will not be able to sell the extracted energy, or at least force the counter to spin in the opposite direction.
The use of solar panels is advantageous in that they provide a more universal form of energy, but it can not match the efficiency of solar collectors. However, these do not have the ability to store energy, unlike solar photovoltaic panels.
How to calculate the required capacity of the reservoir
When calculating the required power of the solar collector is very often mistakenly perform calculations on the basis of the incoming solar energy during the coldest months of the year.
The fact that the whole system is constantly overheating in the rest of the year. The temperature of the coolant in the summer at the output of the solar collector can reach 200 ° C at a heating steam or gas, 120 ° C antifreeze, 150 ° C water. If the coolant boils, it is partially evaporated. As a result, it will have to be replaced.
Manufacturing companies recommend come from the following figures:
- provision of hot water is not more than 70%;
- ensuring the heating system is not more than 30%.
The rest of the heat required should develop a standard heating equipment. However, at these rates annually it saves an average of about 40% on heating and hot water.
Power generated by the single tube of the vacuum system depends on the geographical location. Figure of solar energy per 1 m2 of land falling in the year called insolation. Knowing the length and diameter of the tube, it is possible to calculate the aperture - the effective absorption area. It remains to apply coefficients of absorption and emission power for computing one tube per year.
Calculation example:
Standard tube length of 1800 mm, an effective - 1600 mm. Diameter 58 mm. Aperture - shaded area created by the tube. Thus the shadow area of the rectangle:
S = 1,6 * 0,058 = 0,0928m2
the average efficiency of the tube is 80%, the solar insolation for Moscow is about 1170 kWh / m2 per year. Thus one tube will produce in a year:
W = 0,0928 * 1170 * 0.8 = * h 86,86kVt
It should be noted that this is a very approximate calculation. The amount of energy produced depends on the installation orientation, angle, an average temperature, etc.
Useful videos on the topic
Demonstration of action of the solar collector in the winter:
Compare different models of solar collectors:
During the whole of its existence mankind more and more energy is consumed every year. Attempts to use free solar radiation were made long ago, but only recently became possible to use the sun in our latitudes effectively. There is no doubt that the future of solar systems.
