Solar panels for summer cottages and houses: types, principle of operation and procedure for calculating solar systems

Example of calculating the energy consumption of appliances

There is always a refrigerator, TV, computer, washing machine, boiler, iron, microwave and other household appliances in the house, without which life becomes uncomfortable. In addition, at least 100 light bulbs are used for lighting (let them be energy efficient). All this should be taken into account when calculating the power of solar panels installed in the house.

The table provides data on their power, operating time, energy consumption, etc. All of them work all year round:

device	Power	Duration of use per day	Daily consumption
Light bulbs for lighting	200 W	about 10 hours	2 kWh
Fridge	500 W	3 hours	1.5 kWh
Notebook	100 W	up to 5 hours	0.5 kWh
Washing machine	500 W	6 hours	3 kWh
Iron	1500 W	1 hour	1.5 kWh
Television	150 W	5 o'clock	0.8 kWh
Boiler 150 liters	1.2 kW	5 o'clock	6 kWh
inverter	20 W	24 hours	0.5 kWh
Controller	5W	24 hours	0.1 kWh
Microwave	500 W	2 hours	3 kWh

Having made a simple calculation, we come to the final daily energy consumption - 18.9 kW / h. Here you need to add the power of additional equipment, which is not used every day - an electric kettle, a kitchen combine, a pump, a hair dryer, etc. On average, at least 25 kW / h will be obtained per day.

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Therefore, the monthly energy consumption will be 750 kWh. In order to cover current costs, the solar battery must produce at least the final figure, i.e. 750 kW.

What benefits does the owner of the house receive after installing solar panels

The installation of photovoltaic converters makes it possible to receive electricity regardless of resource providers. If a set of solar panels is used as an additional source of energy, then it becomes possible to significantly reduce electricity costs.

Another point that may soon become important for owners of autonomous power plants. The government plans to introduce a new procedure for paying for electricity with the owners of autonomous complexes connected to the grid.

For the energy that a private power system gives to the network, the owner will receive a certain fee. So far, this is only a project, but it will soon come into force, stimulating the development of renewable energy sources. Thus, installing solar panels can allow you to earn some money, which is never superfluous.

The main characteristics of solar panels for the home

Starting to consider the topic of solar panels, first of all, you need to pay attention to the photovoltaic power supply system. This device converts sunlight into electrical energy.

For two hundred years, mankind has been improving this equipment, and successfully. That is why every day more and more people are interested in installing a solar battery.

But which one to choose There are three types of systems, depending on the specifics alternative energy source.

The first type is characterized by open photovoltaic power supply systems (PPS). They do not have batteries, and the equipment itself is powered through a special inverter. The main network will not work if the generated power is greater than the consumed.

The second type is characterized by autonomous systems that are independent of the main network. PSE of this kind function in their outline of the network for direct power supply of all equipment. The best performance is observed when there is a battery that uses the accumulated energy during the deterioration of solar energy, and also if the generated power is greater than the consumed.

The third types include the combination of the two previous categories. Combined PSE have great functionality.There is even the possibility of transferring unused generated energy to the main grid. But this type of system is the most expensive.

How to choose?

Installing a solar system on your own site will cost a decent amount. Before proceeding with the installation of a solar battery, it is necessary to determine the required power for all devices. And first of all, it is necessary to calculate the optimal peak load in kilowatts and a rational conditionally average energy consumption in kilowatts / hours to meet the needs of a house or site.

For the rational use of solar electricity, it is necessary to determine:

• peak load - to determine it, it is necessary to add the power of all devices turned on at the same time;
• maximum power consumption - a parameter necessary to determine the category of devices that must work at the same time;
• daily consumption - is determined by multiplying the individual power of a single device by the time during which it worked;
• average daily consumption - is determined by adding the energy consumption of all electrical appliances in one day.

All these data are necessary for the assembly and stable subsequent operation of the solar battery. The information obtained will make it possible to select more suitable parameters for the battery pack, an expensive element of the solar system.

To carry out all the calculations, you will need a sheet in a cage or, if you prefer to work on a computer, it will be most convenient to use an Excel file. Prepare a table template with 29 columns.

List the column names in order.

• The name of an electrical appliance, household appliance or tool - experts recommend starting to describe energy consumers from the hallway, and then moving around clockwise or counterclockwise. If the house has more than one floor, then the starting point for all subsequent levels is the staircase. And also indicate street electrical appliances.
• Individual power consumption.
• Time of day from 00 to 23 hours, that is, for this you need 24 columns. In the columns over time, you will need to enter two numbers in the form of a fraction: the duration of work during a particular hour / individual power consumption.
• In column 27, enter the total operating time of the appliance per day.
• For column 28, it is necessary to multiply the data from column 27 by the individual power consumption.
• After filling in the table, the final load of each device is calculated for each hour - the data obtained is entered in the 29th column.

After filling in the last column, the average daily consumption is determined. To do this, all the data in the last column are summarized. However, this calculation does not take into account the consumption of the entire solar collector system. To calculate these data, it is necessary to take into account the auxiliary coefficient in the final calculations.

Such a careful and painstaking calculation will make it possible to obtain a detailed specification of energy consumers, taking into account hourly loads. Since solar energy is very expensive, its consumption must be minimized and rationally used to power all appliances.For example, if the solar collector will be used as a backup power supply for the house, then the data obtained will make it possible to exclude energy-intensive devices from the network until the main power supply is finally restored.

In order to constantly supply the house with energy from the solar battery, hourly loads are moved forward in the calculations. Electricity consumption must be adjusted in such a way as to exclude emergency situations during system operation and equalize maximum loads.

This graph clearly shows how to rationally use the energy of the sun in the house. The initial graph shows that the load was distributed randomly during the day: the average daily hourly rate was 750 W, and the consumption rate was 18 kW per hour. After accurate calculations and competent planning, it was possible to reduce the daily consumption to 12 kW / h, and the average daily hourly load to 500 watts. This power distribution option is also suitable for backup power.

The principle of operation of the solar battery

The device is designed to directly convert the sun's rays into electricity. This action is called the photoelectric effect. Semiconductors (silicon wafers), which are used to make elements, have positive and negative charged electrons and consist of two layers, the n-layer (-) and the p-layer (+). Excess electrons under the influence of sunlight are knocked out of the layers and occupy empty places in another layer. This causes free electrons to constantly move, moving from one plate to another, generating electricity that is stored in the battery.

How a solar battery works depends largely on its design.Solar cells were originally made from silicon. They are still very popular, but since the process of cleaning silicon is quite laborious and costly, models are being developed with alternative photocells from compounds of cadmium, copper, gallium and indium, but they are less productive.

The efficiency of solar panels has increased with the development of technology. Today, this figure has increased from one percent, which was recorded at the beginning of the century, to more than twenty percent. This allows us to use panels today not only for domestic needs, but also for production.

Specifications

The device of the solar battery is quite simple, and consists of several components:

Directly solar cells / solar panel;

An inverter that converts direct current to alternating current;

Battery level controller.

Batteries for solar panels buy should be based on the necessary functions. They store and distribute electricity. Storage and consumption occurs throughout the day, and at night the accumulated charge is only consumed. Thus, there is a constant and continuous supply of energy.

Excessive charging and discharging of the battery will shorten its useful life. Controller solar battery charge automatically stop the accumulation of energy in the battery when it has reached the maximum parameters, and turn off the load of the device in case of strong discharge.

(Tesla Powerwall - a 7 kW solar panel battery - and home charging for electric vehicles)

network inverter for solar The battery is the most important design element. It converts the energy received from the sun's rays into alternating current of various capacities.Being a synchronous converter, it combines the output voltage of electric current in frequency and phase with a stationary network.

Photocells can be connected both in series and in parallel. The latter option increases the power, voltage and current parameters and allows the device to work even if one element loses functionality. Combined models are made using both schemes. The service life of the plates is about 25 years.

Scheme of solar power supply

When you look at the mysterious-sounding names of the nodes that make up the solar power system, the thought comes to the super-technical complexity of the device. At the micro level of the life of a photon, this is so. And visually the general scheme of the electrical circuit and the principle of its operation look very simple. There are only four steps from the luminary of heaven to the “bulb of Ilyich”.

Solar modules are the first component of a power plant. These are thin rectangular panels assembled from a certain number of standard photocell plates. Manufacturers make photopanels different in electrical power and voltage, a multiple of 12 volts.

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Solar panels are used in regions with a low number of cloudy days, operate them as a primary or secondary energy supplier

It makes sense to build a solar panel system in areas with little infrastructure that are not yet connected to centralized power grids

In the summer, at their summer cottage, solar appliances will be able to provide energy for electrical appliances and a heating system.

Equipment for monitoring the operation and adjustment of solar panels does not take up much space, usually includes an inverter, controller and battery

If there is a free, well-lit area on the site, a solar power plant can be placed on it

With good protection against atmospheric negativity, the control and monitoring devices for the operation of the solar battery can be located outdoors

solar power plant for a private house can be assembled from factory-made batteries

A solar battery assembled from silicon wafers will be much cheaper and almost equal in performance.

Installation of solar panels on roof slopes

Installation on terraces, verandas, attic balconies

Solar system on the sloping roof of the extension

Indoor unit solar mini power plant

Location on the free site of the site

Outdoor-built battery box

Assembling a solar panel from ready-made batteries

Making a solar battery with your own hands

Flat-shaped devices are conveniently located on surfaces open to direct rays. Modular blocks are combined by means of mutual connections to form a solar battery. The task of the battery is to convert the received energy from the sun, giving out a constant current of a given value.

Batteries are known to all devices for the accumulation of electric charge. Their role within the system of energy supply from the sun is traditional. When household consumers are connected to a centralized network, energy storage devices are stored with electricity. They also accumulate its surplus if there is enough current from the solar module to provide the power consumed by electrical appliances.

The battery pack supplies the circuit with the required amount of power and maintains a stable voltage as soon as the consumption in it rises to an increased value. The same thing happens, for example, at night with non-working photo panels or during low-sunshine weather.

The scheme of energy supply at home with the help of solar panels differs from options with collectors by the ability to store energy in a battery (+)

The controller is an electronic intermediary between the solar module and batteries. Its role is to regulate the battery charge level. The device does not allow them to boil from overcharging or the electric potential to fall below a certain norm, which is necessary for the stable operation of the entire solar system.

Inverter - reversing, so the sound of this word is literally explained. Yes, because in fact, this node performs a function that once seemed fantastic to electrical engineers. It converts the direct current of the solar module and batteries into alternating current with a potential difference of 220 volts. It is this voltage that is working for the vast majority of household electrical appliances.

The flow of solar energy is proportional to the position of the luminary: when installing modules, it would be good to provide for adjusting the angle of inclination depending on the season

How it works

The SBItak system, a solar battery, is a system of interconnected elements, the structure of which allows, using the principle of the photoelectric effect, to convert sunlight falling on them at a certain angle into electric current.

A system that converts sunlight into electrical energy consists of the following components:

1. Semiconductor material (tightly combined two layers of materials with different conductivity).It can be, for example, single-crystal or polycrystalline silicon with the addition of other chemical compounds that make it possible to obtain the properties necessary for the occurrence of the photoelectric effect.

   For the transition of electrons from one material to another, it is necessary that one of the layers has an excess of electrons, and the other one has a lack of them. The transition of electrons to a region with their deficiency is called a p-n transition.

2. The thinnest layer of an element that resists the transition of electrons (placed between these layers).
3. Power supply (if connected to the opposing layer, electrons can easily overcome this barrier zone). So there will be an ordered movement of infected particles, called electric current.
4. Accumulator (accumulates and stores energy).
5. charge controller.
6. Inverter-converter (converting the direct current received from the solar battery into alternating current).
7. Voltage stabilizer (designed to create a voltage of the desired range in the solar battery system).

Scheme of operation of a solar panel Photons of light (sunlight) falling on the surface of a semiconductor when colliding with its surface transfer their energy to the electrons of the semiconductor. The electrons knocked out by impact from the semiconductor overcome the protective layer, having additional energy.

Thus, negative electrons leave the p-conductor, passing into the conductor n, positive - vice versa. Such a transition is facilitated by the electric fields existing in the conductors at that time, which subsequently increase the strength and difference of charges (up to 0.5 V in a small conductor).

Intending to purchase a solar panel or make it, carefully calculate:

• the cost of such a battery and the necessary equipment;
• the amount of electrical energy you need;
• the number of batteries you need;
• number of sunny days per year in your area;
• the area you need to install solar panels.

I start collecting

Before buying and assembling, it is necessary to calculate the entire system so as not to be mistaken with the location of all systems and cabling. From solar panels to the inverter, I have about 25-30 meters and I laid two flexible wires with a cross section of 6 sq. mm in advance, since voltage up to 100V and current 25-30A will be transmitted through them. Such a margin over the cross section was chosen to minimize losses on the wire and deliver energy to the devices as much as possible. I mounted the solar panels themselves on self-made guides from aluminum corners and attracted them with self-made mounts. To prevent the panel from sliding down, a pair of 30mm bolts looks up on the aluminum corner opposite each panel, and they are a kind of “hook” for the panels. After installation, they are not visible, but they continue to bear the load.

How to benefit from

Given the property of the panels to work only in sunny weather, it is necessary to study in detail the market for solar panels, namely the material from which they are made. Polycrystalline panels are able to perfectly generate not only direct sunlight, but also scattered rays. And the clouds required for the operation of installations and solar radiation are no longer an obstacle. In order to obtain greater efficiency, even in cloudy weather, polycrystalline silicon batteries should be selected.

Precipitation, in particular snow, in a certain sense, is not a minus at all. When snow falls, the volumes of reflected rays increase.And if silicon solar cells are present in the panels, the amount of stored energy increases. When installing the panels, one should also keep in mind the snow issue, there is a need for frequent cleaning of the panels from snow.

However, time and progress do not stand still, and perhaps in the near future batteries will be developed by the power of thought, without any shortcomings and minuses. And humanity will take confident steps in the direction of preserving nature, the atmosphere and the planet.

How many inverters should be in the system

In theory, 1 device of the required power should be enough for the entire power plant. But, if you have a large number of photocells and they are assembled in several lines, it is better to put such a converter on each of them.

Why is that? The fact is that the unstable operation of one line, for example, it is not located on the sunny side, will adversely affect the operation of the inverter and its efficiency will be generally lower

If it is important to get the maximum efficiency of the power plant, this option is not suitable.

An alternative option is an inverter for several independent MMP inputs. There can be 2-4 of them and such models are much more expensive.

Solar panel efficiency in winter

You will probably be surprised, but on a winter day only 1.5-2 times less energy falls on a vertical surface than in summer. This data is for central Russia. During the day, the picture is worse: during this period in the summer we get 4 times more energy

But pay attention: on a vertical surface. That is on the wall.

If we talk about the horizontal surface, then the difference is already 15 times.

The saddest picture of solar power generation awaits you not in winter, but in autumn: in cloudy weather, their efficiency is 20-40 times lower, depending on the density of cloud cover. In winter, after snow fell, insolation (the amount of light falling on batteries) on sunny days can approach summer values. Therefore, solar systems for the home generate more electricity in winter than in autumn.

It turns out that in order to achieve close to maximum efficiency in winter, you need to place solar panels vertically or almost vertically. And, if you hang them on the walls, then preferably in the southeast: in the morning, according to statistics, there is more often clear weather. If there is no southeast wall, or it is impossible to install anything on it, you can get out of the situation by making special stands. Then they put solar panels on the roof. Since the angle of incidence of sunlight varies depending on the season, it is advisable to make a stand with an adjustable tilt angle. There is an opportunity - turn the solar panels "face" to the southeast, there is no such possibility, let them "look" to the south.

One of the mounting systems

What to look for when choosing solar panels

Due to the fact that the use of solar energy for domestic purposes has not yet become commonplace, and the choice of solar panels causes certain difficulties, we offer a list of the most important parameters

So, when buying such a module, you should pay attention to the following points: manufacturer

manufacturer.

It is important to pay attention to how long this manufacturer has been on the market for this product, and what is its production volume. The longer a manufacturer has been in the industry, the more they can be trusted.

area of ​​use.

For what purposes will the received energy be used: for charging small appliances, for powering large electrical appliances, for lighting, or for a full-fledged power supply at home. The choice of the output voltage and power of the panels depends on the purpose for which the solar module is bought.

voltage.

For small electrical appliances, 9 V is enough, for charging smartphones and laptops - 12-19 V, and for providing the entire power system at home - 24 V or more.

power.

This parameter is calculated on the basis of the average daily energy consumption (the sum of the energy consumed by all appliances per day). The power of solar panels should cover consumption with some margin.

quality of photovoltaic cells.

There are 4 quality categories of photocells that make up the solar panel: Grad A, Grad B, Grad C, Grad D. Naturally, the first category is best - Grad A. The modules of this quality category do not have chips and microcracks, are uniform in color and structure, have the highest efficiency and are practically not subject to degradation.

life time.

The service life of solar panels varies from 10 to 20 years. Of course, the duration of the full operation of such a power system depends on the quality of the batteries and the correct installation.

additional technical parameters.

The most important are efficiency, tolerance (power tolerance), temperature coefficient (the effect of temperature on battery performance).

Having understood the main technical characteristics, we offer you a rating of the best solar panels in 2020.

Conclusions and useful video on the topic

The principles of operation and connection schemes for solar panels are not too difficult to understand.And with the video materials we have collected below, it will be even easier to understand all the intricacies of the functioning and installation of solar panels.

It is accessible and understandable how a photovoltaic solar battery works, in all details:

How solar panels work:

Assembling a solar panel from photocells with your own hands:

Each element in the solar power supply system of the cottage must be selected correctly. Inevitable power losses occur in the batteries, transformers and controller. And they must be reduced to a minimum, otherwise the rather low efficiency of solar panels will be reduced to zero altogether.

Alternative energy sources are becoming more and more important every day. The reason for this is environmental friendliness, renewability, low cost. Solar energy is one of the most profitable sources of energy. For the next few billion years, it will continue to illuminate our planet, giving off a huge amount of energy, unlike gas and oil. Today we have learned how to use this source with a solar panel system, but few people understand the principle of operation of the solar battery.
Let's figure it out.

First you need to understand what home solar power system
it is not only those black or bluish panels that are installed on the roofs of houses. These light receivers are only one of the four components of the overall system, which includes: