Chilled Water Research Articles

Using building cooling for load shifting on a 5-minute wholesale energy market

To achieve carbon neutrality there must be a significant increase in the proportion of renewable generation. Energy storage and demand flexibility will accommodate more solar and wind generation. Some energy markets in Australia, northern Europe and the USA have moved or are moving to a 5-min settlement period to increase energy flexibility. Commercial building’s HVAC systems could capitalise on new market conditions through 5-min load shifting strategies that have negligible impact on occupant comfort. Here the effectiveness HVAC load shifting strategies for cost arbitrage in 5-min wholesale electrical energy markets are examined. Five strategies are compared using global zone setpoint adjustment and chilled water leaving setpoint adjustment. Results show significant energy flexibility can be achieved without violating occupant comfort. High priced 5-min settlement periods can be successfully coasted over with no HVAC energy consumption for temperatures under 36 °C. Over a 10 week period the case study achieved 14.2% energy cost savings.

Energy Consumption and Energy Saving Analysis of Air-Conditioning Systems of Data Centers in Typical Cities in China

The energy consumption status and energy saving potential of the air-conditioning systems of data centers in seven typical cities in China (Xinjiang, Beijing, Jinan, Shanghai, Nanning, Guilin, and Haikou), representing diverse climate regions, were studied. The power usage effectiveness (PUE) and cooling load factor (CLF) were taken as the evaluation indicators. First, the energy consumption situations of the existing air-conditioning systems were analyzed using an internship survey. Second, the meteorological data throughout the year for the seven cities were statistically analyzed. Then, two energy saving renovation schemes were proposed. The operating hours under different operating modes in the seven cities were calculated, and the PUE and energy saving potential of the two energy saving schemes were evaluated by taking the production of 15 °C chilled water as an example. This study provides an overall picture of the energy utilization status in the current Chinese data center market and provides solutions for improving the design of air-conditioning systems, with energy saving benefits.

Modeling of the Operational Parameters on the Performance of an Air Conditioning System

Heat and moisture are removed from occupied spaces by air conditioning systems. Air conditioners regulate moisture and temperature, and improve air quality. Human efficiency is dramatically boosted and worker's efficiency is affected by their work environment. Human being is more comfortable and productive with air conditioning. After a few years of excellent operation, the system began to fail, resulting in numerous resident complaints. The goal of this study is to establish operational characteristic models for an air conditioning system's performance in order to fulfill future client requirements. The inlet and output temperatures as a function of local time were measured for the LSBLG 1200/MCF model central water chiller air conditioning system. The COP and EER curves were examined. MiniTAB 16.0 was used to establish the characteristic curves and models, according to the findings. The regression models are statistically significant at 97.7 percent and 91.1 percent for p-value less than 0.05 and R2 , respectively. The COP and EER values were calculated, and it was determined that the best cooling occurred between 1 and 3 p.m. The chiller and cooling tower achieve maximum coefficients of performance (COP) of 52 and 20, respectively. The chiller and cooling tower have EER ratings of 177 and 68, respectively. Regression analysis is used to develop models that characterize the statistical relationship between operational parameters such as input and outlet temperatures as a function of local time and response variables such as COP and EER. The performance of the system can be monitored using existing models. Keywords: Modeling, operational parameters, performance, and air conditioning system.

Effect of flow channel structures and refrigerants on the motor cooling process of compressor with gas bearings

Energy-saving and environment-friendly water chiller is the development trend. The efficient compressors and new refrigerants are hot spots. The gas bearing can significantly improve the performance of centrifugal refrigeration compressors, and effective motor cooling is the guarantee of performance and reliability. The influence of channel structure and refrigerant on the performance of the motor cooling process and refrigeration system is analyzed. The results show that adding the bearing gas supply circuit decreases the motor temperature and the maximum variation of permanent magnet temperature is about 60 °C. The cooling channel structure in the interlayer of the motor shell will affect the cooling process. The spiral channel can reduce the stator temperature and improve the uniformity of temperature distribution. But the temperature of the motor changes slightly when the length of the channel is more than 6000 mm. The motor temperature is the highest with refrigerant R1234ze(E), followed by it R1234yf and R134a. The maximum temperature of the permanent magnet for R1234ze(E) is 20–50 °C higher than it for R1234yf and 50–60 °C higher than it for R134a under different inlet diameters. The maximum temperature of the permanent magnet for R1234ze(E) is 30 °C higher than it for R1234yf and 50 °C higher than it for R134a under different inlet temperatures. The system with a motor cooling circuit has controlled the motor temperature within the safe operation range, while the COP of systems with R134a, R1234yf, and R1234ze(E) has only decreased by 4.63 - 5.36%, 4.22 - 4.6%, and 3.78 - 4.15% respectively.

Use of High-Pressure Processing to Improve the Redness of Dark-Cutting Beef

The objective was to evaluate the effects of high-pressure processing (HPP) levels on retail color of dark-cutting beef. Eight USDA Choice (mean pH=5.5; normal-pH beef) and 12 dark-cutting (mean pH=6.3) strip loins were obtained from a commercial packing plant within 2 d of harvest. Dark-cutting loins were cut into equal sections, vacuum packaged,and randomly assigned to 0 (no HPP), 300, 450, and 600 MPa of pressure for 90 s using chilled water. Following 48 h of dark storage at 2°C, dark-cutting loin sections were cut into 1.9-cm-thick steaks, placed in Styrofoam trays overwrapped in polyvinyl chloride (PVC) film, and placed in a simulated retail display for 8 d. The surface color readings were measured every 24 h using a HunterLab MiniScan XE Plus spectrophotometer, whereas a trained color panel (n=6) evaluated dis-coloration, paleness, and lean color on steaks. Lipid oxidation was evaluated on day 0, 4, and 8 of retail display, and structural changes were determined using light microscopy on day 0 of display. There was a significant HPP level×day of retail display interaction for all instrumental color measurements. Throughout the retail display, L* values of 450 and 600 MPa applied steaks were greater (P<0.05) than 300 MPa and controls. There was a significant pressure level×day of retail display interaction when panelists evaluated lean color and discoloration. Steaks treated at 300 MPa exhibited brighter red color and lower (P=0.0023) thiobarbituric acid reactive substance values than other pressure levels and normal-pH control steaks. Light microscopy analysis indicated that HPP increased space between muscle structures. In conclusion, low (300 MPa) and moderate (450 MPa) pressure levels can improve redness of dark-cutting steaks.

Thermal and energy performance evaluation of a full-scale test cabin equipped with PCM embedded radiant chilled ceiling

The escalating global demand for space cooling has led to the emergence of new cooling technologies, including the phase change material embedded radiant chilled ceiling (PCM-RCC) system. This technology improves energy efficiency and indoor environmental quality, while also offering demand-side flexibility. The present study experimentally evaluates the thermal efficiency and energy performance of a PCM-RCC system in a full-scale test cabin equipped with PCM panels. Here, the transient thermal behaviour of PCM ceiling panels besides the cooling energy delivered during charging-discharging cycles are examined. The indoor thermal comfort and peak electricity demand reduction enabled by the present PCM-RCC are also discussed. The results reveal that chilled water circulation for 4–5 h overnight was sufficient to fully recharge the PCM panels. Over 80% of the occupancy time was classified as “Class B″ thermal comfort according to ISO 7730. The system's daily electricity usage was mostly concentrated during off-peak hours, accounting for ∼70% of the total usage. While the controlling schedule used in this study responded to the transient thermal behaviour of the indoor space and PCM ceiling panels, a more dynamic, predictive schedule is necessary to improve the system's overall efficiency and further enhance indoor thermal comfort in response to the changing environmental conditions.

Experimental investigation of the cooling capacity and thermal performance of the passive displacement dual cooling coil system in tropical climate

This paper focuses on the application of Passive Displacement Dual Cooling Coil (PDDCC) system in an indoor space based on a test lab. Parametric study, first, was carried out using Computational Fluid Dynamics (CFD) simulation to identify the optimum fall duct design for the PDDCC unit. Thermal profiles obtained through the simulations indicated that the fall duct with 300 mm height and 0° taper angle was most suitable as it generated the largest volume of cool air which sufficiently cooled the space. It was then applied to the experiment of the PDDCC units in the test lab to study the system's thermal performance. The total cooling load removed by the two PDDCC units within the indoor space varied from 2.24 kW to 2.93 kW. The latent load removal over the entire experiment duration ranged from 0.7 kW to 1.35 kW where the highest latent heat was removed at the lowest chilled water setpoint temperature of 7.5 °C. Thermal stratification trends displayed that temperature within the room for all chilled water setpoint temperatures (7.5 °C, 8.5 °C, 9.5 °C, and 10.5 °C) corresponded with the increase in heat load within the indoor environment. The humidity level above 1 m ground level was not exceed 56%. The PDDCC system was found to have excellent latent heat removal capability. The PDDCC system was able to produce a thermally comfortable environment for 67% of the experimental permutations. The low humidity level within the test cell allowed to raise the boundary of the acceptable temperature range for achieving human thermal comfort to as high as 26.5 °C.

Computational Analysis of the Automation Strategies of Temperatures of Supplied Air, Chilled and Condensation Water in Commercial Buildings

The automation strategies currently used in HVAC systems do not control the system temperature variables (supplied air, chilled, and condensation water temperatures) in an optimized way. Normally, these temperatures are fixed in design conditions, or vary according to the weather conditions. However, studies demonstrate that adequate control of these three temperatures can provide significant reductions in the energy consumption of the air conditioner system. Therefore, this work analyzes the benefits of individualized and integrated automation of these three variable temperatures in different tropical and subtropical weather conditions through computer simulation for a typical commercial building. The results of integrated automation show savings in consumption between 5.03% and 19.68% compared to a fixed control, and between 3.22% and 8.21% compared to a weather-based control alone, showing that the integrated strategies are better than both models adopted as market benchmarks.

Energy Consumption Analysis Using Weighted Energy Index and Energy Modeling for a Hotel Building

Energy consumption is an essential and vital issue for commercial hotel buildings. Regulations and codes are commonly used to regulate the energy usage of the building. However, the energy index used to evaluate energy performance does not include the usage of hotel buildings for different service purposes. This study utilizes a comprehensive approach involving data collection, field measurement, regression analysis, and building energy modeling to investigate the energy performance in hotel buildings. The study finds that ambient temperature and occupancy rate are key factors in energy consumption, resulting in a weighted energy index for public areas and guest rooms with an R-square of 0.8314 and 0.9184, respectively. The measurement data are also used to perform the energy modeling, and the data are validated. Studies on different regions, occupancy, orientation, window-to-wall ratios, and U-values are evaluated and simulated to determine the energy consumption, which might be useful for the hotel building design phase. In addition, it also evaluates the energy-saving potential, including chilled and condenser water temperature, COP, and indoor temperature settings. The study finds that implementing various studies could result in significant energy consumption and savings, with higher chilled water and lower condenser water temperature having a particularly prominent impact. The study concludes that energy modeling approaches can be useful tools for identifying and implementing energy-saving strategies.

Retrofitting conventional chilled-water system to a solar-assisted absorption cooling system: Modeling, polynomial regression, and grasshopper optimization

This study aims to replace the current conventional chilled-water system with solar-assisted absorption cooling in a large pharmaceutical company in Amman, Jordan. Conventional heating, ventilation, and air conditioning (HVAC) systems were used to serve the existing 9000 m2 area of the pharmaceutical facilities. Two solar absorption chiller configurations were proposed and evaluated to investigate this replacement using TRNSYS® software. The auxiliary heater and storage tank were configured in series and parallel and evaluated based on actual data from the company. The effects of the evacuated tube collector (ETC) on the solar fraction, storage tank volume (STV), auxiliary heat required (Qaux), and heat loss (Qloss) were studied. The grasshopper optimization algorithm (GOA), a newly developed optimization technique, was used to optimize the storage tank volume with solar fraction (SF), Qaux, and average heat loss (kJ/h) on an hourly basis in parallel and series configurations. Mathematical equations involving the factor such as storage tank volume and Qloss responses in parallel and series configurations were developed using regression modeling (RM) over all experimental observations. The optimal factor values were then calculated using the GOA and regression models. The confirmation findings indicated that SF was maximized, and Qloss was effectively minimized. Under the 95 % confidence level with = 0.05, the p-value for all RMs was <0.05, indicating the significance of the RM. Furthermore, the RM matched the provided data well, with a low prediction error. The GOA indicated that the parallel system configuration was the superior connection that provided optimum results for SF, and Qaux at a storage tank of 2.8 m3. According to the GOA method, the optimal STV for a series layout was 2.0 m3 and for a parallel arrangement was 2.8 m3. In terms of SF, the parallel system configuration outperformed the series system, which increased by 12.34 %. The parallel system significantly decreases Qloss and Qaux by 4.04 % and 7.39 %, respectively. To compare the GOA with other meta-heuristic optimization approaches, conventional HVAC systems were optimized using particle swarm optimization (PSO). The results indicated that the GOA surpasses the PSO technique in terms of the required convergence speed and population size. Because the movement of agents depends on the positions of each agent inside the swarm, GOA differs from other optimization algorithms. The novelty of this study demonstrates that the GOA technique provides a higher probability of convergence with less computing effort than well-liked and popular optimization methodologies such as PSO for a variety of Qloss, Qaux, and SF issues. These results have significant reverberation for the potential of the GOA to minimize Qloss and Qaux, and maximize SF in the parallel and series configurations of the auxiliary heater.

Transient study of thermal stratification of full-scale chilled water storage tank during optimum discharge condition

Thermal stratification of full-scale Chilled Water Storage Tanks (5855 m3) with 18 m tank diameter, and 23 m water depth during discharge mode and optimum condition was studied. The experimental and numerical analyse of stratified thermal storage tank in full-scale dimension and discharge mode has been studied. A 3D and 2D numerical model was performed. The case simplified to divide into two parts, the first part was to simulate flow in pipes and radial diffuser, and the second part included simulation in the tank according to the part one results. The optimum operation condition which found from many tests of tank operation conditions according to high thermal stratification and low thermal mixing inside the tank. Validation test with experimental data obtained from the present work and literature. The results included to analyse the thermal stratification and the flow characteristics during the discharging mode. Also, thermal performance parameters such as discharge efficiency, Richardson number, stratification efficiency, thermocline thickness, the average temperature in the tank, and discharge temperature were presented. The important result of the above analysis was the optimum stratification phenomena in the tank with low thermal mixing. The contribution of this study was the numerical modelling and simulation setting to capture the experimental results of these phenomena in the full-scale thermal storage tank, moreover to specify the optimum condition of thermal stratification of this tank dimension, diffuser type, and flow rate.

Effects of external weather on the water consumption of Thermal-Energy-Storage Air-Conditioning system

Thermal-Energy-Storage Air-Conditioning (TES-AC), a sustainable form of Air-Conditioning (AC) operates by storing thermal energy as chilled water when energy demand is low during nighttime. Later it uses the stored thermal energy during the daytime to cool the indoor air of the building the next day. However, the stored thermal energy in the form of water in the tanks of the chiller plant might be affected by external weather factors. It is essential to understand whether there is a relation between external weather conditions and water consumption in the TES-AC system. Without verifying the relation, applying computational intelligence for Thermal-Energy-Storage (TES) in Heating, Ventilation, and Air Conditioning (HVAC) would not be appropriate. However, not much research has focused on applying such techniques in HVAC for facility management and maintenance. Moreover, identifying these features by discovering the relation between weather and water consumption is a crucial part to apply computational intelligence such as machine learning techniques for predictive maintenance of this facility as it heavily relies on water volume for TES-AC charging. During warmer weather, the stored thermal energy might have an effectual loss due to evaporation which would mean more water consumption by TES-AC for cooling. Hence, this research investigates whether external weather data has any effect on the water consumption of TES-AC and discusses how external weather may affect the water consumption of TES-AC and if it is important to factor it in whilst utilizing computational intelligence for charging load prediction of TES-AC.

An Outbreak Investigation of Salmonella Typhimurium Illnesses in the United States Linked to Packaged Leafy Greens Produced at a Controlled Environment Agriculture Indoor Hydroponic Operation – 2021

In 2021, the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state partners investigated a multistate outbreak of Salmonella Typhimurium illnesses linked to packaged leafy greens from a controlled environment agriculture (CEA) operation in Illinois. Thirty-one illnesses and four hospitalizations were reported in four states, with a significant epidemiologic signal for packaged leafy greens from Farm A. A traceback investigation for leafy greens included seven points of service (POS) with food exposure data from eight ill people. Each POS was supplied leafy greens by Farm A. FDA investigators observed operations at Farm A and noted that 1) the firm did not consider their indoor hydroponic pond water as agricultural water, 2) condensate dripping from the chiller water supply line inside the building, and 3) unprotected outdoor storage of packaged soilless growth media and pallets used for finished product. FDA collected 25 product, water, and environmental samples from Farm A. The outbreak strain was recovered from a water sample collected from a stormwater drainage basin located on the property adjacent to Farm A. In addition, an isolate of Salmonella Liverpool was recovered from two indoor growing ponds within the same growing house, but no illnesses were linked to the isolate. Farm A voluntarily recalled all implicated products and provided their root cause analysis (RCA) and return-to-market plan to FDA. While the source and route of the contamination were not determined by the RCA, epidemiologic and traceback evidence confirmed the packaged salads consumed by ill persons were produced by Farm A. This was the first investigation of a multistate foodborne illness outbreak associated with leafy greens grown in a CEA operation. This outbreak demonstrated the need for growers using hydroponic methods to review their practices for potential sources and routes of contamination and to reduce food safety risks when identified.

Thermodynamic performance analysis of a novel air conditioning system integrating solar absorption compression refrigeration and vacuum membrane-based dehumidification (SACV)

For solar absorption cooling systems, it is difficult to generate lower chilled water for dehumidifying and cooling, as well as facing intermittency problems. In this work, the novel SACV system for indoor temperature and humidity control is proposed, which integrates the SSAR subsystem, the VCR subsystem, and the VMD subsystem. The VMD subsystem and the VCR subsystem solve the dehumidification difficulty and all-weather heating and cooling problems, respectively. This work also proposes a method for determining the collector area that avoids frequent start-ups and shutdowns of the VCR subsystem. Besides, a thermodynamic model of the SACV system is established and validated, and a systematical performance analysis of the SACV system is carried out. For the SACV system, the sensitivity of the parameters to the MCOP is also discussed. Results indicate that the outdoor air temperature, the latent heat load ratio, and the solar radiation intensity are the key parameters for designing the SACV system; further, the evaporation temperature and the permeate side pressure are the key parameters for the SACV system optimization. The SACV system is more suitable for high-humidity environments. Moreover, during the cooling season, the SACV system of a commercial building can realize a power saving rate of 39.82% compared to the conventional VCR system. The proposed SACV system of a commercial building can reduce 19653.59 kg/year carbon emission compared to the conventional VCR system in Nanjing. The carbon reduction rate of the SACV system in the selected cities is rather similar, about 36.78%–39.79%.

A Review on Green Cooling: Exploring the Benefits of Sustainable Energy-Powered District Cooling with Thermal Energy Storage

This paper examines the economic and environmental impacts of district cooling systems (DCS) that are integrated with renewable energy sources and thermal energy storage (TES). Typically, a DCS offers a highly efficient and environmentally friendly alternative to traditional air conditioning systems, providing cool air to buildings and communities through a centralized system that uses chilled water. However, the integration of renewable energy and thermal energy storage into these systems can further increase their sustainability and efficiency, reducing their dependence on fossil fuels and improving their ability to handle fluctuations in demand. The goal of this paper is to provide a comprehensive review of the current state of the art of renewable energy-driven DCS with TES integrated and to highlight the benefits and challenges associated with these systems. Finally, the findings of this paper offer valuable insights into the potential for renewable energy-powered district cooling systems to contribute to a more sustainable and efficient built environment.

Cooling capacity evaluation of thermally activated light shelf (TALS) systems

A light shelf is typically used to improve the lighting environment by preventing glares and increasing illuminance in interior zones. If its surfaces can be utilized as cooling surfaces it can also be used to control the thermal environment, particularly in perimeter zones. In this study, the concept of a thermally activated light shelf (TALS), wherein a chilled water pipe is embedded in a light shelf, was proposed, and its cooling capacity was experimentally evaluated. As the upper and lower surfaces are exposed to indoor air and cooling loads, which are different from those of conventional radiant cooling panels, a mock-up test chamber was developed to represent the cooling load applied to both the upper and lower surfaces of the TALS. Mock-up experiments were conducted to evaluate the cooling capacity of the TALS alternatives: TALS with thermal insulation (INS case), cavity air (AIR case), and DC fans (FAN case). Compared with the baseline (INS case), the cooling capacities of the AIR and FAN cases were enhanced by 9.4–29.4% and 22.7–53.1%, respectively, because both the upper and lower surfaces could be utilized as cooling surfaces. Based on the experimental results, cooling capacity curves were derived to provide generalized cooling capacity data considering various cooling load conditions, operating conditions (e.g., chilled water temperature and room air temperature), and layer configurations of the TALS.

Design of silica gel/water adsorption chiller powered by solar energy for air conditioning applications

The design and thermo-economic studies for a silica gel/water solar adsorption cooling system are presented in this paper using Simulink to perform a numerical analysis of refrigeration systems employing a pair of silica gel and water. A case study for modelling the adsorption system with several cooling load capacities ranging from 10 to 100 Ton of Refrigeration (TR) was also presented. The simulation output results include the desorber temperature, the temperatures of hot water and chilled cooling, the temperatures of two adsorption/desorption beds, condenser and evaporator, the refrigerant and silica gel mass, area, and cost of all parts in the system, mass flow rate and thermal power. Results showed that the cost of the system and the mass of the silica gel were 20,708.4$ and 2266 kg, respectively for 10 TR cooling load, while for 100 TR cooling capacity, it was 189,169.6$ and 22,667 kg, respectively. Results also showed that when the cooling load increased from 10 TR to 100 TR, the area of the condenser, evaporator, bed, and collector increased, and the mass flow rate of the collector, condenser cooling water, chilled water, and the cooling circuit increased with a percentage increase of 9 times.

Comparative study on different energy-saving plans using water-side economizer to retrofit the computer room air conditioning system

An energy efficient, environmentally friendly and economical retrofit plan of traditional computer room air conditioning system is necessary to reduce energy consumption of data centers. In this study, two energy-saving retrofit plans, a computer room air handler system with water-side economizer (Plan 1) and a loop thermosyphon system with water-side economizer (Plan 2), are compared with an air-cooled computer room air conditioning system (existing cooling system) in a data center. To analyze and compare the energy efficiency, environmental and economic potential, energy models of the existing cooling system and retrofit plans are established. Under different set points (including supply chilled water temperature and supply air temperature) and 2.08–6 kW average electric power of racks, the free cooling periods of Plan 1 and Plan 2 reach 3878–5867 h and 4541–7661 h, respectively, which lead to the annual energy consumption of Plan 1 and Plan 2 decreases by 27.6–47.3% and 53.4–63.6%, respectively. Due to the lower annual energy consumption of main equipment (including chillers, chilled water pumps, cooling water pumps and terminal equipment), Power Usage Effectiveness of Plan 2 is 0.049–0.090 lower than that of Plan 1, and Global Coefficient of Performance of Plan 2 is 23.3–67.3% higher than that of Plan 1. Furthermore, the annual CO2 emissions of Plan 1 and Plan 2 are 337.3–557.1 tons and 599.8–1106.9 tons less than those of the existing cooling system at different operating stages respectively. Finally, the dynamic payback periods of Plan 1 and Plan 2 are 4.11–5.42 years and 1.64–3.57 years.

Dynamic simulation study on regulation characteristics of transcritical CO2 multi-ejector refrigeration system

This paper presents a dynamic model of transcritical CO2 refrigeration system with multi-ejector which is developed based on the real CO2 properties and considering the internal transonic flow, phase change and choking, and its predictions are in good agreement with experimental data from the literature. The transient response of the system is studied by adjusting the speed of compressor, water flow of heat exchanger, opening of expansion valve and combination of ejector as disturbance conditions. The presented results show that the developed dynamic model has similar response rules with the same type of system. Changes of cooling water flow of gas cooler and chilled water flow of flooded evaporator can cause significant response of other pressures in the system except low-temperature evaporator, and can regulate the cooling and heating load to some extent. Opening of medium and low temperature expansion valve plays a decisive role in the system's medium and low temperature refrigeration capacity respectively, and the low-temperature expansion valve is the only regulation means of the low-temperature cooling capacity. Optimal operating combination of multi-ejector maximizes the system performance and ejector pressure lift ratio. Furthermore, the optimal ejector combination of the system under the refrigeration capacity of 75∼115 kW is studied and compared, a control strategy of adjusting ejector combination by "nozzle mass flow rate" is put forward to adapt to the high-performance operation of the system under different loads. Under the research conditions, the optimal ejector combination satisfies that the nozzle mass flow rate is stable in 0.066∼0.070 kg·s-1.

Modelling and performance assessment of a Tri–Generation cooling system using two adsorption chillers under Jordanian climate

In this study, the performance of a Tri-Generation cooling system employing two adsorption chillers will be analysed experimentally and theoretically utilizing the TRNSYS software. The purpose of this study is to assess the performance of two adsorption chillers and to evaluate how operational and design factors affect the performance of the tri-generation cooling system.The system was developed and validated at the Mutah University in Jordan, it consists of 240 m2 parabolic trough solar matrix. The trough matrix heated thermal oil to 260 °C, producing 13.7 bar of 210 °C superheated steam. The power cycle is completed by evaporating brackish water with the engine's 120 °C steam. Distillation yields 150 L of distilled water each hour. The rejected heat from distillation is stored in a thermally isolated hydraulic storage tank and used to power a unique two-stage air cooled adsorption chiller with a cooling capacity of 10 kW each.As a result, adsorption chillers' COP and normalized capacity were calculated. Their optimum values were obtained at 94 °C hot water, 15 °C chilled water, and 35 °C condensation temperature. The lowest COP and normalized capacity values were recorded at 65 °C hot water, 7 °C chilled water, and 38 °C condensation temperature.