Exergy Analysis and Thermoeconomics of Buildings Design and Analysis for Sustainable Energy Systems by Sala-Lizarraga, Jose M; Picallo-Perez, Ana | 9780128176115 | 0128176113 | Holooly

Engineering Economy

Exergy Analysis and Thermoeconomics of Buildings Design and Analysis for Sustainable Energy Systems

138 SOLVED PROBLEMS

Question: 8.3

We refer to the same facility as in Example E.8.1 but, in this case, the PF(R) formulation is used. That is to say, it is about a DHW production facility using a condensing boiler. The system consists of a boiler, a hydraulic compensator, a three-way valve acting according to the demand, a heat ...

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The components considered for the analysis are sho...

Question: 6.16

In an experimental plant of a Renewable Energy Laboratory, three types of solar installations are available: (1) 5 m² of flat solar collectors that heat a water flow of 76 L/h from 12°C to 40°C. (2) 2.4 m² of vacuum tube collectors that produce a mass flow of 0.4 g/s of saturated steam at 100°C ...

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(a) The incident radiation on flat collectors is 4...

Question: 8.2

We refer to the same installation considered in Example E.8.1, that is to say, a DHW production facility with a condensing boiler. The system consists of a condensing boiler, a hydraulic compensator, a three-way valve acting according to the demand, a heat exchanger and an accumulation tank. In ...

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(a) The facility’s functional analysis is done in ...

Question: 9.5

Inverse problem with several anomalies. Heating and DHW installation We consider again the installation of Example E.9.1, to which the two anomalies of Example E.9.2 are incorporated. As we have said, one of them is in the RS radiator system, with a 10% decrease in its efficiency and the other is ...

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Since 13 components have been considered, 13 chara...

Question: 6.2

Let there be a LiBr/H20 single effect absorption refrigerator, as shown in the diagram in Fig. E.6.1. The generator is driven by a flow of hot gases, while the condenser and absorber give heat to the ambient air which is at 35°C. In the evapo-rator, a flow of water is cooled from 18°C to 12°C. The ...

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(a) The heat given up by the hot gas to the genera...

Question: 7.13

In an adiabatic combustion chamber, a fuel mass flow rate of 15 g/s of specific exergy 52.1 MJ/kg is consumed. A flow of hot gases, whose exergy is 120 kW, is produced. This flow is passed through an expander, where an electrical po-wer of 20 kW is produced, leaving a flow of gases still hot with ...

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(a) Undertaking a balance of exergy costs in the c...

Question: 7.12

Consider again the schema of the installation in Fig. 7.3 corresponding to Example E.7.2, and determine: (a) The exergy costs of flows. (b) The exergy costs of the fuel and products of the equipment. ...

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(a) To obtain the exergy costs of the flows, we ne...

Question: 7.11

Consider again the schema of the installation in Fig. 7.1 corresponding to Example E.7.1. Determine: (a) The exergy costs of the flows. (b) The exergy costs of the fuel and products of the equipment. ...

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(a) To obtain the exergy costs of the flows, we ne...

Question: 6.5

An airflow of 3800 kg/h at 2°C is taken from the outside with a relative humidity of 70%, passing through an electrical resistance where it is heated up to 12°C. Then, that air is mixed with another flow of air at 20°C saturated with humidity, so that the mass flow rate of saturated air is double. ...

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(a) Calculating the absolute humidity of the outsi...

Question: 7.4

In the cross-flow heat exchanger in Fig. E.7.6, with 1, 2 being the cold flow states at the inlet and outlet and 3, 4 the corresponding states of the hot flow, define F and P, as well as the exergy efficiency of the equipment in the following two cases: (a) When T1>T0, and the purpose of the ...

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(a) Since the purpose of the exchanger is to heat ...

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