Thermal Storage Air Conditioning Research Articles

Examination of Operational Methods for a Low-Temperature Aquifer Thermal Storage Air Conditioning System Based on Operational Performance and Considerations of Thermal Storage and Pumping Volume Balance

Aquifer Thermal Energy Storage (ATES) systems are garnering attention as high-efficiency air conditioning technologies that contribute to the realization of a carbon-neutral society. This study focuses on an ATES system constructed in Japan, characterized by its complex geological conditions and thin aquifer layers. Detailed actual performance data measured over four years are presented, and performance analysis results show that a COP of 5 was achieved for the overall building cooling and heating system. In addition, the study provides a detailed analysis of the imbalance in heat quantity, remaining heat storage, and other factors based on actual data, identifying operational issues and summarizing specific improvement measures. Finally, as a proposal for a sustainable operational method to balance the cumulative heat storage and pumping volume of cold and hot water, specific operational procedures are summarized, including setting the return water temperature for the next season based on the dimensionless average pumping temperature of the previous season, and a flowchart is presented. There is no prior research that shows such specific operational procedures, and this can be considered an important achievement of this study.

Receding‐horizon based optimal dispatch of virtual power plant considering stochastic dynamic of photovoltaic generation

AbstractThe merits of a virtual power plant in integrating photovoltaic generation and flexible loads, such as a chilled water thermal storage air conditioning system and an electric vehicle, are well recognized. However, the optimal operation of a virtual power plant is challenged by the complexities of solar irradiance and the large size of a chilled water thermal storage air conditioning system and an electric vehicle. This paper proposes a new approach to the optimal dispatch problem of a virtual power plant. The stochastic dynamic of solar irradiance is modelled by a stochastic differential equation set. The binary decision for a chilled water thermal storage air conditioning system and an electric vehicle are characterized by a mixed logical dynamical model. The resulting optimal dispatch problem is solved by the receding horizon approach. The appeal of the proposed approach is in its capability to consider the stochastically dynamical impact of solar irradiance. Besides, the proposed approach can solve the optimization problem over a relatively small period of time, and thus has the potential for online applications. Finally, the feasibility and effectiveness of the proposed approach is demonstrated by numerical simulations.

Optimal Dispatch of a Virtual Power Plant Considering Demand Response and Carbon Trading

The implementation of demand response (DR) could contribute to significant economic benefits meanwhile simultaneously enhancing the security of the concerned power system. A well-designed carbon emission trading mechanism provides an efficient way to achieve emission reduction targets. Given this background, a virtual power plant (VPP) including demand response resources, gas turbines, wind power and photovoltaics with participation in carbon emission trading is examined in this work, and an optimal dispatching model of the VPP presented. First, the carbon emission trading mechanism is briefly described, and the framework of optimal dispatching in the VPP discussed. Then, probabilistic models are utilized to address the uncertainties in the predicted generation outputs of wind power and photovoltaics. Demand side management (DSM) is next implemented by modeling flexible loads such as the chilled water thermal storage air conditioning systems (CSACSs) and electric vehicles (EVs). On this basis, a mixed integer linear programming (MILP) model for the optimal dispatching problem in the VPP is established, with an objective of maximizing the total profit of the VPP considering the costs of power generation and carbon emission trading as well as charging/discharging of EVs. Finally, the developed dispatching model is solved by the commercial CPLEX solver based on the YALMIP/MATLAB (version 8.4) toolbox, and sample examples are served for demonstrating the essential features of the proposed method.

Experimental investigation of solar photovoltaic operated ice thermal storage air-conditioning system

Under the double pressure of energy shortage and environmental pollution, ice thermal storage air-conditioning and photovoltaic air-conditioning has been applied in refrigeration field. In order to improve application scope and reduce investment operation cost, the ice thermal storage adopted to store solar energy in ice thermal storage air-conditioning driven by distributed photovoltaic energy system was proposed in this paper. Two operation models had been tested by experiment. Research results revealed all of the solar energy accepted by PV array had been stored with ice or cold water. Moreover, the experimental results analysis showed that it is feasible to use ice thermal storage instead of battery bank to store solar energy in the field of distributed photovoltaic refrigeration. In operation mode 1, the average system energy utilization efficiency was 0.525 and the average refrigeration efficiencies η¯rand η¯rs were 0.7292 and 0.0690, respectively. When system operated in mode 2, the average system energy utilization efficiency was 0.3377 and the refrigerator performances parameters η¯rand η¯rs were 4.49 and 0.3875, which were 6.16 times and 5.62 times of the average η¯r and η¯rs under working model 1.

建物群における水蓄熱空調システムの運用最適化手法に関する研究 （第3報）設定値変更前後の実測値の比較と設定値検討ツールの開発

建物群における水蓄熱空調システムの運用最適化手法に関する研究 （第3報）設定値変更前後の実測値の比較と設定値検討ツールの開発

放冷冷水の冷却水化による蓄熱式空調システムの昼間電力消費削減に関する研究 : 第1報-基本システムの提案と基本性能

放冷冷水の冷却水化による蓄熱式空調システムの昼間電力消費削減に関する研究 : 第1報-基本システムの提案と基本性能

放冷冷水の冷却水化による蓄熱式空調システムの昼間電力消費削減に関する研究(第3報)空冷冷凍機システムへの適用

放冷冷水の冷却水化による蓄熱式空調システムの昼間電力消費削減に関する研究(第3報)空冷冷凍機システムへの適用

Reduction of Electric Power Consumption for Thermal Storage Air Conditioning System in Daytime by Application of Discharged Cold Water to Cooling Water : Part 2-Parallel Operation of Heat Storage Tank Discharged and Application of Discharged Cold Water to Cooling Water for Refrigeration

Reduction of Electric Power Consumption for Thermal Storage Air Conditioning System in Daytime by Application of Discharged Cold Water to Cooling Water : Part 2-Parallel Operation of Heat Storage Tank Discharged and Application of Discharged Cold Water to Cooling Water for Refrigeration

Energy efficient hybrid nanocomposite-based cool thermal storage air conditioning system for sustainable buildings

The quest towards energy conservative building design is increasingly popular in recent years, which has triggered greater interests in developing energy efficient systems for space cooling in buildings. In this work, energy efficient silver–titania HiTES (hybrid nanocomposites-based cool thermal energy storage) system combined with building A/C (air conditioning) system was experimentally investigated for summer and winter design conditions. HiNPCM (hybrid nanocomposite particles embedded PCM) used as the heat storage material has exhibited 7.3–58.4% of improved thermal conductivity than at its purest state. The complete freezing time for HiNPCM was reduced by 15% which was attributed to its improved thermophysical characteristics. Experimental results suggest that the effective energy redistribution capability of HiTES system has contributed for reduction in the chiller nominal cooling capacity by 46.3% and 39.6% respectively, under part load and on-peak load operating conditions. The HiTES A/C system achieved 27.3% and 32.5% of on-peak energy savings potential in summer and winter respectively compared to the conventional A/C system. For the same operating conditions, this system yield 8.3%, 12.2% and 7.2% and 10.2% of per day average and yearly energy conservation respectively. This system can be applied for year-round space conditioning application without sacrificing energy efficiency in buildings.

Thermodynamic model of a thermal storage air conditioning system with dynamic behavior

A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system’s dynamic behavior, such as a dynamic air flow rate into the vehicle’s cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle’s cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid–air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semi-analytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid–air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system experimental data for solidification using paraffin wax as the PCM. Through modeling, we demonstrate the importance of capturing the airside heat exchange impact on system performance, and we investigate system response to dynamic operating conditions, e.g., air recirculation.

Cumulative exergy analysis of ice thermal storage air conditioning system

Based on the cumulative exergy analysis method, the effect of incorporating the Ice Thermal Storage (ITS) air conditioning system in power supply is analyzed. Not only the cumulative exergy of air conditioning system is considered, but also that of the processes consuming the power generated by the same peak regulating unit. The results show that the total cumulative exergy consumption of all processes consuming the power supplied by the peak generating unit, increases as the ITS system is applied. However, the average cumulative exergy variation, which is the ratio between the increment of the cumulative exergy consumption (ΔCEx) and the cooling load of the ITS system (QITS), decreases slightly as QITS increases. It exhibits a linear relationship with the operating load of the power generating unit and QITS. And, it decreases as either of the two parameters increases. These results are verified by two case studies.

A study on demand response effect of thermal storage air-conditioning systems in consideration of electricity market prices

This paper evaluates the economic impact of the introduction of customer-owned Thermal Storage Air-conditioning (TSA) systems, in an electricity market, from the viewpoint of the load service entity (LSE). We perform simulations on the condition that several thousand customers install TSA systems and shift peak demand in an electricity market by one percent. Our numerical results indicate that the purchase cost of the LSE was reduced through load management of customers with TSA systems. The introduction of TSA systems also reduced the volatility of the market clearing price and reduced the whole-trade cost in an electricity market. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 18–27, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21091

A Study of Demand Response Effect of Thermal Storage Air-Conditioning Systems in Consideration of Electricity Market Prices

This paper evaluates the economic impact of the introduction of customer-owned Thermal Storage Air-conditioning (TSA) systems, in an electricity market, from the viewpoint of the load service entity. We perform simulations on the condition that several thousand customers install TSA systems and shift peak demand in an electricity market by one percent. Our numerical results indicate that the purchase cost of the LSE was reduced through load management of customers with TSA systems. The introduction of TSA systems also reduced the volatility of market clearing price and reduced the whole-trade cost in an electricity market.

C-24 杭基礎を利用した自然エネルギーによる土壌蓄熱空調システムの分析 : (その2)シミュレーションによるシステムの運転方法の検討

C-24 杭基礎を利用した自然エネルギーによる土壌蓄熱空調システムの分析 : (その2)シミュレーションによるシステムの運転方法の検討

Study on the Installation of Thermal Storage System in Residential Houses

In recent years, residential houses have become more airtight and better insulated, and some, along with the IT revolution have been equipped with SOHO applications. This leads to a decrease in the heating load, while increasing electricity consumption in the daytime. On the other hand, electricity demand has increased in the summer, while the load rate of equipment in electricity plants has been decreased. Here a new thermal storage air conditioning system, using direct heat exchange, is proposed for a residential house, while its possibility and availability have been studied according to the prediction of energy consumption, which demonstrates the effectiveness of the thermal storage system for residential houses.

00/02155 Need for thermal-storage air-conditioning in Saudi Arabia

00/02155 Need for thermal-storage air-conditioning in Saudi Arabia

Need for thermal-storage air-conditioning in Saudi Arabia

In Saudi Arabia, the growth of demand for electrical energy in the rapidly expanding towns, cities and industries, far exceeds the growth of the power being made available. Recently the Saudi Consolidated Electric Companies (SCECO) are facing a shortage of electricity during the summer period mainly due to the high consumption of electricity in the air conditioning sector. The incorporation of thermal energy storage (TES) technologies with a conventional air conditioning system is found to be an appropriate solution for energy-demand management. In this paper an introductory overview of thermal storage air conditioning is presented, comparing phase change (e.g. ice) and sensible heat (e.g. chilled water) storage technologies. The pros and cons of each are evaluated. The suitability of TES technology for the Saudi HVAC (heating, ventilating and air conditioning) industry is explored with the benefits to the owner such as: reduced energy consumption; less operation and maintenance costs; and downsizing of the chiller plant and system for new facility; alternative to new chiller installation to cater for increased cooling load; and stored water as a fire protection source. Furthermore, an economic study has been presented to illustrate the feasibility of TES based air conditioning in Saudi Arabia.