Cooling Air Conditioning System Research Articles

Heat transfer performance analysis of seawater heat exchange pipelines in deep seawater closed cooling air conditioning system

The efficiency improvement of traditional seawater source heat pump system is limited and pipelines of the open seawater cooling air conditioning system experience scaling and corrosion. To overcome these problems, this paper proposes a deep seawater closed cooling air conditioning system. The system directly uses the closed heat exchange pipeline to exchange heat with the deep seawater and extracts the seawater cooling capacity for cooling. Numerical simulation is used to study the effects of different pipe diameters, flow rates, and inlet water temperatures on the heat transfer performance of vertical inlet sections, submarine heat exchange coils and vertical outlet sections. Since seawater has temperature and flow rate gradients in the vertical direction, the use of a hydraulic calculation table of the vertical pipe section and the calculation diagram of design and selection line of submarine heat exchange coil is proposed. Insulating subsections of the outlet section by dividing the section into 3 °C based on the seawater temperature is proposed. And the subsection insulation layer thickness corresponding to different pipe diameters are given. This study proposes a calculation method for the selection of key design parameters of deep seawater closed cooling air conditioning systems, providing a new method for making full use of seawater resources.

Performance Study of a Two–Stage Evaporative Cooling Air Conditioning System with Internally Cooled Desiccant Beds

Performance Study of a Two–Stage Evaporative Cooling Air Conditioning System with Internally Cooled Desiccant Beds

Construction of Regional Cooling and Heating Source Air Conditioning System Based on Ocean Thermal Energy and Energy Consumption Analysis

Zhao, S.; Yan, P.; Zhao, C., and Chang, H., 2019. Construction of regional cooling and heating source air conditioning system based on ocean thermal energy and energy consumption analysis. In: Li, L.; Wan, X., and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research, Special Issue No. 98, pp. 22–25. Coconut Creek (Florida), ISSN 0749-0208.The ocean contains a huge amount of ocean thermal energy (OTE). The cooling and heating source heat-pump air conditioning system based on OTE collects thermal energy from seawater; then with the aid of the compressor system and a small amount of electricity consumption, it can heat or cool the buildings within the region. By conducting exergy analysis on the system and comparing it with the energy consumption of the air source heat-pump system, it shows that in case of equal heating and cooling supply, the heat-pump energy consumption and system energy consumption of the regional cooling and heating source air conditioning system based on OTE are significantly lower than those of the air source heat-pump system, and it can save about 25% of the energy.

Evaporative Cooling System for Air Conditioning

Evaporative Cooling System for Air Conditioning

Performance assessment and multi objective optimization of an Organic Rankine Cycle driven cooling air conditioning system

Present work aims to investigate the thermal performance assessment of different combinations of working fluids for an Organic Rankine Cycle powered Vapor Compression Cycle (ORC-VCC) for air-conditioning applications. Analysis of system performance is conducted for a fixed cooling load of a small conditioned space having a sensible heat factor of 0.7, at different ambient conditions. A preliminary evaluation of the system at the baseline conditions was conducted considering the second law efficiency, overall heat capacity of exchangers, overall internal exergy destruction, and overall Coefficient of Performance. Afterwards, parametric study was performed for the best performing candidates from the preliminary analysis using second law efficiency and overall heat capacity of heat exchangers. The system parameters considered for the study include saturated temperatures of heat exchangers, ORC boiler superheat, pinch points and the sub-cooling of both the ORC and VCC condensers. Then, multi objective optimization was performed using Genetic Algorithm followed by multi-criteria decision-making using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to select the best optimal solutions from the Pareto front. Sixteen combinations comprising of four working fluids, R245fa, R600, R600a, and R134a were analyzed. The optimization results showed R245fa ORC-R600a VCC to be the best candidate at ambient conditions of 30 °C, while at 35 °C and 40 °C, R600a ORC-R245fa VCC was found to be the most suitable candidate.

Optimization of Water Consumption in Hybrid Evaporative Cooling Air Conditioning Systems for Data Center Cooling Applications

ABSTRACTIn the light of its potential to reduce energy consumption when coupled to the condenser of existing vapor compression systems, evaporative cooling technology still faces questions relating to its water consumption pattern and the effect of water quality on its performance. This paper presents an experimental investigation of the water consumption characteristics in a split air-conditioning system employing evaporative precooling of air flowing over the condenser coils. The effect of the cooling pad thickness on the coefficient of performance of the system is investigated by varying the pad thickness from 5 to 15 cm in step size of 5 cm. Condition of the exit air from the pad shows that evaporative cooling can be employed as a standalone method for cooling of data centers, with adequate humidity control systems in place. Results obtained on water consumption shows that the volume of water consumed does not increase proportionally with time, rather it increases by a factor of 1.8, 2.5, and 3.2, for 2, 3, and 4 hours of operation respectively, relative to 1hour of operation. Two parameters; salinity and turbidity were used to study the effect of water quality on the evaporative cooling process. Additionally, a method of optimizing the pump operation is introduced in this paper. Running the pump intermittently could cut the energy consumed by the water pump in such a hybrid system by up to 20%.

Design method of radiant cooling area based on the relationship between human thermal comfort and thermal balance

The radiant cooling air conditioning system has been widely applied, due to its features of better thermal comfort and efficient energy-saving. Most of the research on radiant cooling air conditioning system tends to concentrate on its cooling performance and energy-saving potential. However, the design methods of radiant cooling air conditioning system to guide its engineering application are rare. On the basis of the simplified human thermal balance equation and the linear relationship between the sensible heat loss and human thermal comfort achieved in our previous studies, the cooling performance of cooled surface is analyzed and then the method for determining the area of cooled surface is proposed in this paper. The numerical model is validated by experimental data and the calculation methods of cooled area are investigated with different boundary conditions. In addition, the PMV values in different heights and around human body are analyzed in detail. The results show that the calculation methods on account of the features of cooled surface could accurately predict the cooled area to maintain human thermal comfort under different conditions. Therefore, it is possible to determine the area of cooled surface in view of the relationship between human thermal comfort and thermal balance. This study could provide the guidelines for both the assessment of human thermal comfort and the system design of radiant cooling air conditioning system.

業務用ビルを対象とする液冷空調システムの開発 （第7報）ヒ－トポンプ熱源を利用するデシカント空調システムにおけるCOPの検討

業務用ビルを対象とする液冷空調システムの開発 （第7報）ヒ－トポンプ熱源を利用するデシカント空調システムにおけるCOPの検討

業務用ビルを対象とする液冷空調システムの開発 （第3報）内部負荷液冷システムの概要と内部発熱機器の実稼働状態での負荷特性把握

業務用ビルを対象とする液冷空調システムの開発 （第3報）内部負荷液冷システムの概要と内部発熱機器の実稼働状態での負荷特性把握

業務用ビルを対象とする液冷空調システムの開発 （第10報）ZEBエネルギー管理システムの検討

業務用ビルを対象とする液冷空調システムの開発 （第10報）ZEBエネルギー管理システムの検討

業務用ビルを対象とする液冷空調システムの開発 （第１報）液冷空調システム導入の必要性、および開発課題

業務用ビルを対象とする液冷空調システムの開発 （第１報）液冷空調システム導入の必要性、および開発課題

業務用ビルを対象とする液冷空調システムの開発 （第8報）結露リスク評価手法の構築

業務用ビルを対象とする液冷空調システムの開発 （第8報）結露リスク評価手法の構築

業務用ビルを対象とする液冷空調システムの開発 （第6報）内部負荷液冷システム仕様検討のための執務室内の対流・放射連成解析

業務用ビルを対象とする液冷空調システムの開発 （第6報）内部負荷液冷システム仕様検討のための執務室内の対流・放射連成解析

業務用ビルを対象とする液冷空調システムの開発 （第2報）モデル建物とモデル空調システムの検討

業務用ビルを対象とする液冷空調システムの開発 （第2報）モデル建物とモデル空調システムの検討

業務用ビルを対象とする液冷空調システムの開発 （第11報）液冷空調システムの構成と省エネルギー効果

業務用ビルを対象とする液冷空調システムの開発 （第11報）液冷空調システムの構成と省エネルギー効果

業務用ビルを対象とする液冷空調システムの開発 （第16報）ヒ－トポンプ熱源を利用するデシカント空調システムの実測評価

業務用ビルを対象とする液冷空調システムの開発 （第16報）ヒ－トポンプ熱源を利用するデシカント空調システムの実測評価

業務用ビルを対象とする液冷空調システムの開発 （第17報）液冷配水システムにおける配水特性の把握と漏水検出手法の検討

業務用ビルを対象とする液冷空調システムの開発 （第17報）液冷配水システムにおける配水特性の把握と漏水検出手法の検討

業務用ビルを対象とする液冷空調システムの開発 （第12報）対流・放射連成解析による冷房方式と液冷熱回収ユニットの検討

業務用ビルを対象とする液冷空調システムの開発 （第12報）対流・放射連成解析による冷房方式と液冷熱回収ユニットの検討

業務用ビルを対象とする液冷空調システムの開発 （第15報）CRIを用いたフロア全体のPMV分布の期間計算

業務用ビルを対象とする液冷空調システムの開発 （第15報）CRIを用いたフロア全体のPMV分布の期間計算

業務用ビルを対象とする液冷空調システムの開発 (第19報) 回収熱利用吸着式冷凍機の開発

業務用ビルを対象とする液冷空調システムの開発 (第19報) 回収熱利用吸着式冷凍機の開発