Scientists have counted that reserves of natural fuel in 50 years will be exhausted completely therefore search of alternative energy sources is already now run. Owner-occupied dwellings can be provided with the electric power at the expense of the sun, wind or water. But before the choice of alternative source or purchase of the reserve generator it is necessary to calculate how many electric power is necessary to ensure trouble-free operation of all consumers of current if to include them at the same time.
It is required to you
- - technical data sheets on all objects of energy consumption;
- - calculator.
Instruction
1. The easiest way to find power consumption – to put indicators of consumption of all electric devices in the house. It is possible to find these indicators in technical data sheet of the device.
2. It is necessary to consider features of starting currents which arise at start of work of energy-requiring object. These indicators can exceed the average values specified in the passport. Consumers of the electric power with induced and pure resistance at whom energy leaves on heating – plates irons, glow lamps have identical operating voltage and at the time of start-up therefore at calculation of total power their indicators just develop.
3. Objects with condenser (capacitive) resistance at which part of energy turns into heat and other part on creation of magnetic field, can consume at start energy much more, than in normal operating condition. Therefore, before calculation of total consumption it is necessary to increase indicator of each such object by 2.5-3 to exclude system overload.
4. Use the following formula for calculation of the consumed energy: PE = 1.1 * (To ¹ * NME ¹ * To start-up ¹ + To² * NME² * To start-up² + …), where PE – total power, To – quantity of one type of the energy-requiring device, NME – the power rating of the device, To start-up – coefficient of starting current.
5. Calculation stages following: - determine the power rating of all electric devices by technical data sheet; - calculate device power indicator taking into account tension at the time of start-up; - summarize all received indicators; - increase the received sum by 1.1 (that is add 10% for reserve stock that the power supply did not work very hard).
6. Example: in the house of 5 sources of energy consumption: plate (NME = 900 W), 2 glow lamps (NME = 2*100 W), fridge (NME = 600 W) and TV (NME = 500 W). The fridge and the TV have condenser resistance therefore they need to be corrected on coefficient of starting current 2.5. Decision: according to formula 1.1 * (1*900*1 + 2*100*1 + 1*600*2.5 + 1*500*2.5), total power will be 4.235 kW. Respectively, the electric energy source has to have power not less than 4.3 kW.
7. The average country house needs the electric generator with power of output current about 6 kW. The cost of the wind generator of such power is about $16,000, the solar battery will cost $19,000. Let yet not everyone be able to afford similar installations, but in the near future many will be forced to pass to consumption of alternative electric energy sources.