Calculation of a solar power plant for the home

The issue of generating electricity by alternative methods is quite relevant in our time. One of the options for providing electricity to the house is the installation of a solar power station. This option can be used as an additional alternative source of electricity or as the main one, if there is a task of power supply at home in the absence of the ability to connect to electrical networks, for example, because of their remoteness.

The first stage in the implementation of this idea is the calculation of the future solar power station. In this article, we give recommendations that will help to correctly calculate the required power of a future solar power station and correctly assess the possibility of implementing this idea depending on various factors.

Initial data

First of all, it is necessary to determine what tasks a future power plant should fulfill. The most important issue is the availability of centralized power supply and its reliability.

First option

The house is connected to electric networks, but the power supply is unreliable and there is a problem of frequent power outages. In this case, it is necessary to determine what tasks a home solar power plant should perform.

If power outages are short, the task of an alternative source of electricity is to provide power to the most important electrical appliances.

It is necessary to analyze which electrical appliances will be used during the period of power outage, and record their power and operating time for further calculations.

Second option

The same initial data as in the first version, but the interruptions in the power supply are long and it is required to implement a backup source of power supply, supplying all the necessary household electrical appliances that are operated daily in the house. We also record the power and duration of electrical appliances.

Third option

The house does not have a connection to electric networks and there is no possibility of connection for one reason or another. In this case, the solar power station will act as the main source of electricity for the house.

If the issue of power supply at home is being addressed for the first time, then it is necessary to think over which electrical appliances it is planned to operate in the house and choose their power, guided by the principle of economy, that is, choose the minimum power, since the cost of a solar power plant directly depends on its power.

The implementation of the idea of ​​a solar power plant is quite costly, so you need to very responsibly approach the issue of calculating future loads and consider all possible options.

Calculation of loads of electrical appliances

When calculating the loads of electrical appliances, it is necessary to separately consider each of the electrical appliances, analyzing all the possible nuances of its operation.

It is immediately necessary to weed out all electrical appliances whose functions can be implemented in another way, without the use of electricity.

We list electrical appliances that are impractical to power from a solar power station and the corresponding alternative replacement:

• electric furnace, electric kettle, electric heaters. If an electric furnace is used for cooking in the house, then in the event of a power outage, you can build a solid fuel furnace, where you can cook food, heat water, and also use it to heat the house. As a backup option, you can purchase a gas stove with a cylinder;

• electric water heater.An alternative is a solar water heater or the implementation of heating water from a furnace; - well water pump. In case of power outages, the possibility of manual intake of water from the well should be provided. If there is no connection to the power grid for convenience of daily operation, you can include the pump in the list of loads that will be powered by the future power plant;

• grits, a mill and other devices used in housekeeping. In this case, manual devices may be preferred.

Separately, it should be said about the lighting of the house. If there is a centralized power supply for everyday use, any type of lamp is selected based on personal preferences. And for autonomous power supply it is necessary to give preference to the most economical types of lamps from the available assortment - that is, LED. It is necessary to choose the optimal number of lamps and their power in order to provide the desired level of illumination in a particular place.

The house has electrical appliances and devices that have great power, but are rarely used. It is impractical to take into account the power of these electrical appliances when designing a solar power plant, since the cost of the power plant will increase significantly, but basically this power will not be used. Such devices include a welding machine, an electrified tool (angle grinder, rotary hammer, processing machines, etc.).

In the absence of a centralized power supply for the operation of such electrical appliances, it is advisable to purchase diesel (gasoline) generator. The presence of a generator in the house gives the advantage that if the solar panels have not charged the battery, then you can replenish the lack of charge by turning on the generator.

For greater efficiency, reliability and load-bearing capacity, it is more advisable to implement autonomous power supply at home using two alternative sources - solar panels and wind generators.

More on the topic:Wind generators or solar panels, which is better to choose?  

The presence of wind generators allows you to increase the total power of autonomous power supply and, possibly, all electrical appliances, including powerful ones, can be operated without the need for a generator. In any case, it is necessary to consider the option of combining two sources of alternative electricity, without giving preference to only one of the options.

For a detailed example of calculating the total electricity consumption and selecting equipment for a home solar power station, see the articles by Boris Tsupilo:

An example of calculating solar panels for a home

Inverter selection and battery calculation

Inverter: sine wave or modified sine wave?

How to choose a solar charge controller

Solar Connection Diagram

Installation, connection of solar panels and their installation on the roof

Calculation of the required power of a power plant

The second important parameter is the load capacity of the power plant, that is, the maximum amount of power that a solar power plant can produce.

When calculating the loads of electrical appliances, it is necessary to analyze which electrical appliances will work at the same time, and what maximum power will be required to power them at peak loads. In this case, it is advisable to consider the operation of electrical appliances in such a way that there are no sudden changes in loads.

It is also necessary to take into account the features of the operation of some electrical appliances. For example, you need to take into account the starting currents of the compressor of the refrigerator and the electric motors of various electrical appliances.

The limit of power output by a power plant limits inverter - a device that converts a direct current battery into alternating current 220 V.

When calculating the power of the inverter, one should also take into account the characteristics of the battery, which accumulates the electricity generated by solar panels. In this case, we are talking about the maximum allowable discharge currents of the battery.

To protect the inverter of the solar power station from overcurrents, in particular overloads, it is used circuit breaker. To control and limit loads, you can use the load priority relay. Household appliances are divided into several groups according to the degree of importance (priority), a load limit is set.

During the operation of electrical appliances, the load priority relay will monitor the load value in real time, and if the set limit is exceeded, it will disconnect part of the load with lower priority, preventing the circuit breaker from tripping and, accordingly, de-energizing the most important electrical appliances.

Calculation of the power of solar panels

A solar power plant produces electrical energy only during daylight hours, if there is sufficient light output. Solar panels must have such power that they can accumulate in the batteries such an amount of electrical energy that will provide power to all household electrical appliances during the day.

There are reference books on the level of solar radiation and solar insolation for each region - usually these data are provided by solar panel implementers. The level of solar radiation shows the approximate amount of electricity generated by solar panels at different times of the year. The solar insolation index allows you to take into account possible worsening weather conditions and to obtain a more accurate value of the generated power by solar cells.

Please note that the reference data are indicative and do not always correspond to the actual characteristics of the solar panels.

When building a home solar power station, it is necessary to provide for the possibility of increasing its capacity in the future by connecting additional solar panels and batteries to accumulate the generated electricity.

As mentioned above, it is necessary to analyze the relevance of the use of another alternative source of electricity in order to ensure an adequate supply of autonomous power supply at home, taking into account all possible factors.

Based on the power of the solar panels, select controllerby means of which the generated electricity is transferred to the battery.

A very important criterion is the availability of funds for the implementation of an autonomous source of power supply at home. Therefore, when choosing certain elements, you need to adjust your choice based on your budget.