**3.2 Considerations regarding the assessment of a typical household required power**

According to Siemens, buildings account on about 40% of global energy consumption and 21% of greenhouse gas emissions, respectively. Consequently, buildings represent the key to reduce energy consumption and support sustainable urban development. The use of modern technology in intelligent buildings can reduce emissions to 40% without affecting the comfort of residents.

Thus, the intelligent house concept is evolving in response to technological progress regarding distributed energy sources as well as information and telecommunication technology, so that through management systems, consumers can contribute to more efficient use of electric power. The use of smart home energy management systems will allow the end users to efficiently use low-cost electric or thermal power [20].

According to the 2016–2030 Romania's Energy Strategy, [21], with 2050 perspectives, the electricity consumption for 2016 by its destination is shown in **Figure 7**. The used electric power in MW by activity sectors is also indicated by **Figure 8**.

According to the 2016–2030 Romania's Energy Strategy, [21], with 2050 perspectives, the share of household consumption will not change significantly. Due to technological progress, it is still possible that the energy share is related to a household to vary between certain limits depending on the appliances within.

**Figure 7.** *Diagram regarding the final electric power consumption [MW] [21].*

*Micro-Grids - Applications, Operation, Control and Protection*

**48**

**Figure 6.**

**Figure 5.**

*Power supply device for low-power equipment [19].*

*Power supply infrastructure for office equipment [18].*

have adjustable frequency and/or voltage. Usually, inverters are used to drive AC motors with adjustable rotational speed but are also applicable to other domains, for example, the case of uninterruptible power supplies (UPS). It is therefore necessary to convert the voltage value of about 300 V DC to 220–240 V AC. The on the market wide available solutions usually convert low voltages (12/24/48 V DC) due to the fact that they are required in backup systems which use battery storage for the electric power generated by photovoltaic panels or wind/water turbines. The fact that there is no market for 300 V DC/240 V AC poses a challenge and is due to this system's high price which needs to be produced on special orders. Standard inverters that accept low voltage inputs may be used, but the considered electric grid must

#### **Figure 8.**

*Electric power [MW] by activity sectors [21].*

When discussing 2016, the share of household appliance consumption is shown in **Figure 9**.

At the moment, the price cost of a new household appliance is payed off by lower operating costs (electric power, water or other forms of energy). If considering the share consumption related to household appliances beside the total electric power consumption of the residential sector as well as the life exceeded household appliances in Romania, it becomes obvious that there is a significant potential to reduce the power and water demand, and implicitly final costs, by replacing old equipment with new one, which is much more energy efficient.

Currently, when comparing to other European countries, Romania is characterized by a very low replacement rate of household appliances. In most cases, the average replacement rate exceeds the lifetime of the equipment. These aspects can also represent positive perspectives, namely, the growth potential of new energyefficient household appliance market [21].

Hereinafter, electrical power requirement is estimated by considering various household electrical consumers and appliances generally used. The table below shows the consumers taken into account for the power estimation as well as their characteristics (**Table 2**).

Following the estimation, it is shown that 5 kW is sufficient to supply a typical household. Depending on the season, outside temperature, or time of day, actual consumption may be much lower than anticipated.

If the air conditioning is operating while at the same time an electric vehicle is charging, the consumption is higher (about 50% of the required energy). When these consumers are not connected due to the fact that there is no need for heat/cold or the electric car has enough remaining power, then the local generated energy can be stored in batteries or transferred to the public DC grid.

In order to ensure the energy needs, several power sources can be considered depending on the location's energy potential: photovoltaic panels and wind/ water electric generators. A microgrid based on renewable energy sources can be technically and economically designed in order to provide 5 kW power. A 3 kW photovoltaic panel system provided with maximum power point tracking technology (MPPT) along with a 2 kW wind turbine can generate the required power. The surplus energy will be stored in batteries and used when needed. If the microgrid

**51**

**Table 2.**

**Figure 9.**

*Assessment of the Main Requirements and Characteristics Related to the Implementation of…*

is designed to work on-grid and not autonomously, public AC grid access will be

*DOI: http://dx.doi.org/10.5772/intechopen.84413*

opted via AC/DC bidirectional converters.

*The share of household appliance power consumption [21].*

**power**

*Electric consumers considered for the estimation of the necessary power.*

**Absorbed power**

**UM [W] [W] [V DC] [A DC] [min] [h] [kWh/day]** Heat pump 3000 750 375 8.00 15 12 9 Ventilation 250 83 375 0.67 20 18 1.5 Washing machine 2000 1000 375 5.33 30 1 1 Refrigerator A+ 200 50 375 0.53 15 24 1.2 Dishes washing machine 1600 400 375 4.27 15 1 0.4 Lightning 300 300 48 6.25 60 4 1.2 TV + laptop + router 100 100 48 2.08 60 6 0.6 Electric vehicle charger 1500 1500 375 4.00 60 8 12 Power supply pump 1600 267 375 4.27 10 24 6.4 Total 10,550 4450 — 35.4 — — 33.3

**Rated voltage** **Current Using** 

**time/h**

**Total using time/ day**

**Required energy**

**No. Electric consumer Installed** 

*Assessment of the Main Requirements and Characteristics Related to the Implementation of… DOI: http://dx.doi.org/10.5772/intechopen.84413*

is designed to work on-grid and not autonomously, public AC grid access will be opted via AC/DC bidirectional converters.

#### **Figure 9.**

*Micro-Grids - Applications, Operation, Control and Protection*

When discussing 2016, the share of household appliance consumption is shown

Currently, when comparing to other European countries, Romania is characterized by a very low replacement rate of household appliances. In most cases, the average replacement rate exceeds the lifetime of the equipment. These aspects can also represent positive perspectives, namely, the growth potential of new energy-

Hereinafter, electrical power requirement is estimated by considering various household electrical consumers and appliances generally used. The table below shows the consumers taken into account for the power estimation as well as their

Following the estimation, it is shown that 5 kW is sufficient to supply a typical household. Depending on the season, outside temperature, or time of day, actual

If the air conditioning is operating while at the same time an electric vehicle is charging, the consumption is higher (about 50% of the required energy). When these consumers are not connected due to the fact that there is no need for heat/cold or the electric car has enough remaining power, then the local generated energy can

In order to ensure the energy needs, several power sources can be considered

depending on the location's energy potential: photovoltaic panels and wind/ water electric generators. A microgrid based on renewable energy sources can be technically and economically designed in order to provide 5 kW power. A 3 kW photovoltaic panel system provided with maximum power point tracking technology (MPPT) along with a 2 kW wind turbine can generate the required power. The surplus energy will be stored in batteries and used when needed. If the microgrid

At the moment, the price cost of a new household appliance is payed off by lower operating costs (electric power, water or other forms of energy). If considering the share consumption related to household appliances beside the total electric power consumption of the residential sector as well as the life exceeded household appliances in Romania, it becomes obvious that there is a significant potential to reduce the power and water demand, and implicitly final costs, by replacing old

equipment with new one, which is much more energy efficient.

efficient household appliance market [21].

*Electric power [MW] by activity sectors [21].*

consumption may be much lower than anticipated.

be stored in batteries or transferred to the public DC grid.

characteristics (**Table 2**).

**50**

in **Figure 9**.

**Figure 8.**

*The share of household appliance power consumption [21].*


**Table 2.** *Electric consumers considered for the estimation of the necessary power.*
