Category Functional Design of the mCCHP-RES System

Load Estimation

Nicolae Badea

The system load is defined as the load necessary to fill the storage. It is estimated in two situations, namely during the system operation and during the system design. During system design is estimated the monthly load, namely that corresponding to each month of the year. No matter how big is, the estimation is carried out on the base of the monthly consumption, which was obtained by applying the estimation methods presented in the Sect. “Consumption estimation” (and selected in the Sect. 5.5). During system design, the ultimate goals of the load estimation are: (a) sizing the suppliers, so that they can support the estimated load, and (b) assess the performance indicators for structural model.

Table 12 Load sharing of the mCCHP system with thermally compression chil...

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Consumption Aggregating

The residence functional needs are met by incorporating into the system of several consumers as home appliance, with TCC, radiator, heater, and domestic facility. The structure of a mCCHP system with a thermally compression chiller is presented in Fig. 24 in Chap. “Structural Design of the mCCHP-RES System”. The heat load of the mCCHP system must cover the heat consumption of the residence, as well as the heat consumption for cooling. The heat consumption for cooling depends on the coefficient of performance, COPa, of the thermally compression chiller. The COPa of cooling devices is considered equal to 0.8. The monthly power consumption of the residence is considered constant, the entire year...

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Determination of the Specific Consumption

The specific heat, cooling, and power annual consumption for building is obtained by dividing the annual consumption to the TFA of the residence (299 m2) thus:

• for heating, the specific heat annual consumption is obtained by dividing the annual consumption (Eq. 1) to the TFA and resulting:

q = 83.2 (kWh/m2 year)

• for cooling, the specific cooling heat annual consumption is obtained by dividing the annual consumption (Eq. 2) to TFA and resulting:

qC = 44.35 (kWh/m2 year)

• for DHW, the specific DHW annual consumption is obtained by dividing the annual consumption (Eq. 3) to the TFA and resulting:

Table 9 Specific energy consumption less RES

Annual specific consumption

Energetic

class

Specific energy of building

Energetic class of building (less RES)

A

B

Heatin...

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Analytical Estimation of the Global Power Consumption for Domestic Facilities

Using Eq. 41 in Chap. "Structural Design of the mCCHP-RES System”, the lighting energy (ELt) required to fulfill the illumination function is:

where:

Installed power, Pn =12 kW

Constant illuminance factor Fc = (1 + MF)/2 = 0.9

Maintenance factor MF is = 0.8

Daylight time usage tD = to — tN = 2,250 h

Annual operating time to = 2,500 h

Occupancy dependency factor FO = Foc + 0.2 — Fa = 0.5

FOc = 0.8 (fromTable 19inChap. “Structural Design of the mCCHP-RES System”)

Absence factor, Fa = 0.5

Daylight dependency factor Fd = 1 – (Fds Fdc Cds) = 0.81 Daylight supply factor, Fds = a + b ■ Csite = °-81

Fdc = 0.3, from Table 21 in Chap. “Structural Design of the mCCHP-RES System”; CDS = 1.

Values of the coefficients a and b for determining the daylight supply factor was adopted from th...

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Analytical Estimation of the Heat Consumption for Domestic Hot Water

Assuming a temperature difference of Д9 = 50 °C between the hot and cold water sides, and four persons, we determined, with the Eq. 39 in Chap. “Structural Design of the mCCHP-RES System”, the monthly quantity of heat consumed for DHW, as follows:

Table 8 UA—value for building

Envelope heat transfer coefficient (UA conduction)

Building element

U-value

Area

U x Area

Description

Orientation

Element

W/m2 °C

m2

W/°C

South

Walls

0.21

37.2

7.81

Window

1.4

32

44.8

East

Walls

0.21

33

6.93

Window

1.4

6.2

8.68

North

Walls

0.21

61.8

12.97

Window

1.4

6.2

8.68

West

Walls

0.21

41.1

8.63

Window

1.4

3.9

5.46

Ceiling/Roof

0.38

240

91.2

UAenvelope = U X A (W...

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Estimation of the Heat for Global Heating and the Cold for Air-Conditioning

For determining the heat for heating and the cold for air-conditioning, the overall heat transfer coefficient of the building will be used. The building heat loss coef­ficient (UA) is found by identifying every route of heat loss from the building and adding these together. The routes for heat transfer between interior and exterior are through the building envelope, air exchange between inside and outside (infiltra­tion) and through the ground (perimeter). Landscape features in the area, vegetation characteristics, and the influence of the nearby buildings determine local climatic particularities given by the solar irradiation, and by the wind. This is why infor­mation regarding the shading in residence location, architectural orientation (Figs. 8 and 9), and building characteristics sh...

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Consumption Estimation

Nicolae Badea

At residence level, the consumption could be global or specific. Consumption is global when it refers to the whole residence. The global consumption divided to the TFA of the residence building, becomes specific. Moreover, the consumption is estimated for each form of energy consumed and each function of the residence covered.

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System Structural Modeling

Nicolae Badea

Regarding the general structural model, it is shown in Fig. 9 in Chap. “Structural Design of the mCCHP-RES System”. Here, the functional needs of residence are those shown in Fig. 1 in Chap. “Structural Design of the mCCHP-RES System”, namely lighting, ventilation, and cooling, heating, and DHW.

The needs will be met by incorporating into the system of several consumers as home appliance, chiller with thermal compression (TCC), radiator, heater, and domestic facility. Consumptions occasioned by the system operation will be aggre­gated, resulting in heat and power consumption at the system level. To cover these consumptions, three storages will be incorporated, namely the power storage, heat storage, and cold storage...

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