Thermodynamic and thermoeconomic optimization of a cooling tower-assisted ground source heat pump

Sayyadi, Hoseyn; Nejatolahi, Mostafa

doi:10.1016/j.geothermics.2011.06.003

Cited by 21 publications

(20 citation statements)

References 18 publications

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“…The review revealed that a large number of authors considered cost-related factors (e.g., interest, capital, energy tariff) as major optimization parameters. Sayyadi et al [5] carried out a study on the optimization of a cooling tower-assisted ground source heat pump system. This study suggested a method using the total revenue requirements for multi-objective optimization by thermodynamic and economic models.…”

Section: Introductionmentioning

confidence: 99%

Simplified Method of Optimal Sizing of a Renewable Energy Hybrid System for Schools

Kim

2016

Sustainability

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Schools are a suitable public building for renewable energy systems. Renewable energy hybrid systems (REHSs) have recently been introduced in schools following a new national regulation that mandates renewable energy utilization. An REHS combines the common renewable-energy sources such as geothermal heat pumps, solar collectors for water heating, and photovoltaic systems with conventional energy systems (i.e., boilers and air-source heat pumps). Optimal design of an REHS by adequate sizing is not a trivial task because it usually requires intensive work including detailed simulation and demand/supply analysis. This type of simulation-based approach for optimization is difficult to implement in practice. To address this, this paper proposes simplified sizing equations for renewable-energy systems of REHSs. A conventional optimization process is used to calculate the optimal combinations of an REHS for cases of different numbers of classrooms and budgets. On the basis of the results, simplified sizing equations that use only the number of classrooms as the input are proposed by regression analysis. A verification test was carried out using an initial conventional optimization process. The results show that the simplified sizing equations predict similar sizing results to the initial process, consequently showing similar capital costs within a 2% error.

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Section: Introductionmentioning

confidence: 99%

Simplified Method of Optimal Sizing of a Renewable Energy Hybrid System for Schools

Kim

2016

Sustainability

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“…In this connection, the ASHRAE manual [9] was the first to discuss the advantages of a hybrid ground source heat pump (HGSHP) system, which uses a cooling tower as a supplemental heat rejecter. Significant research has been done by now on the application of HGSHP systems [10,11]. While promising, these systems are characterized by an increased complexity when running and maintaining GSHP [12].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields

Mao

Xing

et al. 2015

Sustainability

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Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposition principle. The model takes into account the heat transfer along the borehole, thermal interference between BHEs, and the influence of groundwater flow. The accuracy of the model is validated through comparison with an experiment carried out under intermittent operation. The model makes it possible to analyze the geo-temperature restoration performance and its influencing factors, such as BHE spacing, heat flow rate, operation mode, and groundwater flow. The main conclusions of this work are as follows. The heat transfer along the borehole should be considered when analyzing the geo-temperature restoration performance. When the BHE spacing increases, the soil temperature change decreases and the heat recovery improves. Therefore, adequate borehole separation distance is essential in the case of a multiple BHE system with unbalanced load. The presence of groundwater flow is associated with interference between the BHEs, which should not be ignored. In the case of long-term operation, the groundwater flow is beneficial to the geo-temperature recovery process, even for downstream BHEs. Finally, a greater groundwater flux leads to a better geo-temperature recovery.

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“…The two objective functions studied are the economic and thermodynamic objective functions shown in Equation (20) and Equation (21) …”

Section: Multi-objective Optimizationmentioning

confidence: 99%

Exergy and Thermoeconomic Analysis for an Underground Train Station Air-Conditioning Cooling System

Liao

Chuah

2016

Entropy

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Abstract:The necessity of air-conditioning causes the enormous energy use of underground train stations. Exergy and thermoeconomic analysis is applied to the annual operation of the air-conditioning system of a large underground train station in Taiwan. The current installation and the monitored data are taken to be the base case, which is then compared to three different optimized designs. The total revenue requirement levelized cost rate and the total exergy destruction rate are used to evaluate the merits. The results show that the cost optimization objective would obtain a lower total revenue requirement levelized cost rate, but at the expense of a higher total exergy destruction rate. Optimization of thermodynamic efficiency, however, leads to a lower total exergy destruction rate, but would increase the total revenue requirement levelized cost rate significantly. It has been shown that multi-objective optimization would result in a small marginal increase in total revenue requirement levelized cost rate, but achieve a significantly lower total exergy destruction rate. Results in terms of the normalized total revenue requirement levelized cost rate and the normalized total exergy destruction rate are also presented. It has been shown by second law analysis when applied to underground train stations that lower annual energy use and lower CO 2 emissions can be achieved.

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Thermodynamic and thermoeconomic optimization of a cooling tower-assisted ground source heat pump

Cited by 21 publications

References 18 publications

Simplified Method of Optimal Sizing of a Renewable Energy Hybrid System for Schools

Simplified Method of Optimal Sizing of a Renewable Energy Hybrid System for Schools

Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields

Exergy and Thermoeconomic Analysis for an Underground Train Station Air-Conditioning Cooling System

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