Hot Water Temperature Research Articles

Dynamic simulation and exergy analysis of adsorption chiller powered by low-grade waste heat from a fuel-cell system: Effect of multibed configuration and time constant

Energy usage for space cooling and air conditioning has been rapidly growing in recent years and is expected to increase further owing to global warming and climate change. Adsorption chillers can provide an eco-friendly solution to space cooling because they utilize low-grade thermal energy such as waste hot water produced by the primary power-generation unit. In this study, dynamic analysis of a fuel-cell-system-driven adsorption refrigeration system was performed to expedite the optimal multibed configuration and its operating conditions. The scope of the study was extended to investigate maximizing the waste heat utilization achieved via exergy analysis of multibed configurations. The adsorption-to-desorption time ratio was integrated into the physical configuration of the adsorption chiller, and a new variable was introduced as a “time constant” that controls the cycle time and, under ideal conditions, equates the heating requirements of different bed configurations. Dynamic simulations for different bed configurations were conducted to evaluate the performance, specific cooling capacity, and unutilized exergy in the outlet waste stream. Under the operating conditions of 25 °C and 80 °C cold water and hot water temperatures, respectively, the five-bed configuration with a time ratio of 0.25 proved to be optimal, resulting in increases of 45.8%, 10.2%, and 15.1% in the specific cooling capacity, performance, and exergy efficiency, respectively, compared with those of the conventional two-bed configuration. The four-bed configuration yields very similar results, but with a slightly lower specific cooling capacity.

Optimization of Residential Electricity Consumption based on Multienergy Coordinated Control of Generation, Load, and Storage

Introduction: The power system is translating to the “generation, network, load, and storage multiple coordination control” model, which helps to increase the proportion of renewable energy consumption and reduce the operation cost. Materiala and Methods: The residential electrical system is an important component in the power system, which includes distributed photovoltaic systems, flexible loads, electric vehicles, and battery storage systems, which have the potential to realize multiple coordination control and minimize the net cost of the electricity consumption in a residential electrical system by the coordinated cooperation of generation, flexible loads, and the battery storage system. The comfort level of the residents is also maintained during control. Therefore, a nonlinear economic model is introduced to represent coordinated cooperation of generation, flexible loads, and the battery storage system, and a nonlinear economic predictive controller is proposed to solve the problems of this model. Results: Based on the forecasted generation/load for a tumbling prediction window, the impact of different control trajectories is estimated, then the minimum cost trajectory for flexible loads and battery is selected, and only the first control action is implemented. Then, the prediction window is moved to the next time interval, and the same process is repeated. The case study shows that the proposed method reduces about 24.36% of the net cost of the residential electrical system. Conclusion: Meanwhile, the hot-water temperature and indoor temperature of the household are maintained without affecting the end-user comfort, and the state-of-charge (SOC) for the electric vehicle and the battery system is always kept under constraints without affecting usage. The proposed method has a good performance for the coordinated cooperation of generation, flexible loads, and battery storage system in the residential electrical system. The proposed method also increases the consumption of PV, with the implementation in more residential buildings that will benefit in achieving carbon neutrality by 2060 in China.

Calorimetric determination of wet snow liquid water content: The effect of test conditions on the calorimeter constant and its impact on the measurement uncertainty

The liquid water content (lwc) of wet snow is a fundamental parameter in determining snow properties like its strength and adhesion force to surfaces. Among the different methods available for the measurement of the lwc, this paper focuses on melting calorimetry: known masses of hot water and snow are mixed into a thermally insulated container, and the lwc is obtained from the difference between the initial hot water temperature and the final mixing temperature; it is a fast and easy to implement method that requires little equipment, making it suitable for both laboratory and field measurements. Tests with “equivalent” wet snow samples whose liquid water content was known in advance were carried out to assess the method, showing that the liquid water content was overestimated by a variable amount that seemed to depend on the test parameters. To account for the heat capacity of the calorimeter, which was found not to be negligible, a constant in terms of equivalent hot water mass (E) was introduced. However, its value also depended on the test conditions. Hence, a correlation between E and the test parameters was found, and the measurements were repeated using a container of a different material, showing a similar behavior. Eventually, a discussion about the effects of choosing different hot water masses and hot water-to-snow mass ratios on measurement accuracy is provided.

Performance analysis and optimization of a coupled open and close liquid desiccant sorption system using LiCl solution

The efficient utilization of low-grade heat for air conditioning has been a topic of world concern, especially for low-grade heat below 80℃. In this study, a novel coupled open and close liquid desiccant sorption system driven by 70 ∼ 80℃ low-grade heat is proposed. This system employs a generator to provide strong solution for both the dehumidifier and absorber, achieving the air temperature and humidity independent control to reduce driving temperature and enhance system performance. A mathematical model is developed to simulate the proposed new system, and a comparative analysis is conducted with a traditional combined absorption refrigeration with liquid desiccant dehumidification system using LiCl solution. It is found that the COP of the new system is 0.76, which is higher than 0.65 of the traditional system when the hot water temperature is 75℃, the reason is that the new system avoids the sensible heat consumption of regenerated air which accounts for 17% of the total heat consumption in the traditional system. Furthermore, it is observed that the outlet concentration difference between the absorber and dehumidifier exists in the new system. The cycle is optimized to improve the concentration difference, leading to a 5.5% increase in the COP. After that, economic performance analysis shows a payback period of 2.65 years for a 150 kW cooling capacity system, with a reduction of 86.6 tons of CO2 emissions per year due to the decrease in power consumption.

Comparison of traditional district heating with low temperature district heating systems featuring organic Rankine cycle and heat pump

Paper presents a comparison between a traditional district heating system with conventional boilers as a source of heat and electricity purchases from power utilities and a low temperature DH system incorporating the CHP with organic Rankine Cycle providing electricity and local heat pump raising the temperature of the DH fluid to the required temperature in the dwelling, meaning that both heat and electricity are produced within the system. Additionally, such “island” system may feature or not the heat pump. Comparisons are made based on the results obtained using a developed simple analytical model enabling calculations of the efficiency of respective systems. The analyses have a general character and can be used in studies of complex networks however presented in the paper simple examples show merely the fundamental capabilities of the developed tool. The objective of the heat pump in the system is to increase temperature of hot water to the required level locally at the dwelling and provide the heating in such way, contrary to the traditional system, where water heating is considered by the use of electric heaters to increase parameters of water for central heating purposes and preparation of utility hot water. Presence of the heat pump in the system allows for significantly lower temperatures of distributed in the network heat carrier.

Evaluation of Physical Quality Characterization MRQ 107 Parboil Rice Production Using Selected Parameter

Rice (Oryza sativa L.) is a significant source of nourishment in most Asian countries since it is a primary source of carbohydrates, micronutrients (Fe and Zn) and vitamins, offering broad prospects for food and nutritional security. MARDI’s variety, namely MRQ 107, was chosen for producing parboiled rice using the Response Surface Methodology (RSM) technique at different soaking hours (2, 4 and 6) with steaming time at intervals of 15, 30 and 45 mins with hot water temperature 70ºC and 75ºC. The results have shown that parboiled rice of MRQ 107 process at selected parameter consistently has produced a high milling percentage in the 69-70% range with conversion to Head Rice Yield (HRY) in the range 84%-97%. This finding shows that good quality MRQ 107 parboiled rice can be produced through the parameters selected with a recovery of a high percentage of rice heads (head rice) and has the potential to resolve the economic losses to millers from losing out due to a high rate of broken rice especially during parboiled rice processing.

Experimental study of phase change material performance as thermal insulation of a double-walled spherical tank under partial vacuum for storing solar energy

In solar systems, conservation of stored energy is even more important than energy storage. In this study, as an innovative idea, the thermal behavior of a phase change material (PCM) is investigated as thermal insulation of an energy storage tank based on the unique feature of phase change at a constant temperature. Condition for creating an ideal insulation is the existence of a heat source at the border. The PCM surrounding the tank stores the solar energy latently in the process of thermal charging, and as a heat source in the process of thermal discharge. By releasing energy at a constant temperature through the PCM, the heat loss factor that is the temperature difference between the hot water and the surface of the tank is controlled. The PCM shows three different behaviors as the thermal insulation. One, as long as the energy stored in the PCM is sensibly released, the heat loss coefficient is almost constant, in which the PCM acts as a super insulator. Two, by releasing the latent energy, the heat loss coefficient tends to zero, and the PCM acts as an ideal insulator. Three, by releasing all the stored energy, the PCM acts as a normal insulator. Creating the relative vacuum between the tank and the glass cover improves the thermal performance, thereby the hot water temperature decreases by 7.4 °C in the best case, and the thermal efficiency reaches 85%.

Study of Dynamic Sorption in Adsorption Refrigeration Cycle

This paper shows the characteristics of temperature and adsorbed (water vapor) mass rate distribution in the adsorber unit which is the key part to any adsorption refrigeration system. The temperature profiles of adsorption/desorption phases (Dynamic Sorption) are measured experimentally under the operating conditions of 90oC hot water temperature, 30oC cooling water temperature, 35oC adsorption temperature and cycle time of 40 min. Based on the temperature profiles, The mass transfer equations for the annulus adsorbent bed are solved to obtain the distribution of adsorption velocity and adsorbate concentration using non-equilibriummodel. The relation between the adsorption velocity with time is investigated during the process of adsorption. The practical cycles of adsorption and desorption were stated dependent on the variables obtained from the experiment and equations calculations.The results show that the adsorption velocity is diminished after a period of 20 min. The maximum value of the adsorbed water vapor concentration on silica gel is 0.12 kg water/kg adsorbent (adsorption phase) and the minimum value of the water content into silica gel is 0.04 kg water/kg adsorbent (desorption phase) producing a dynamic sorption of kg water/kg adsorbent.

New zeotropic CO2-based refrigerant mixtures for cascade high-temperature heat pump to reach heat sink temperature up to 180 °C

There is a great demand for clean, high-temperature heating in industries. The present work demonstrates the modeling and analysis of a high-temperature heat pump (HTHP) using a two-stage cascade refrigeration system with newly developed refrigerant mixtures. Environment-friendly CO2/butane and CO2/pentane mixtures were introduced in the Low-stage (LS) and High-stage (HS) cycles, respectively. The model was built in MATLAB and explored the possibilities of high-temperature heating. A heating source temperature of 10 to 50 °C was considered as the system's input. The HTHP was designed to deliver hot water at a temperature above 115 °C. The performance of the system was investigated in terms of the heat sink and hot water temperatures, temperature lift, heating capacity, LS, HS, and total system’s coefficient of performance (COP), volumetric and isentropic efficiencies, and discussed. The analysis indicated that the system could deliver high-temperature water with a temperature lift of 70 °C. Mixtures of 5% CO2/ 95% butane and 5% CO2/ 95% pentane exhibit excellent thermo-physical properties making them suitable for high-temperature heating applications with high COP. For instance, such mixtures obtain the system's COP and heating capacity of 3.6 and 201.5 kW, respectively for the heat sink temperature of 116.7 °C. It shows an improvement of 20% compared to pure fluids. Also, the heat sink temperature could reach up to 181 °C when the CO2 composition in the refrigerant mixtures is 20%. The volumetric (0.72–0.87) and isentropic (0.61–0.71) efficiencies of the compressor were studied and displayed.

Effects of Coupling Combined Heat and Power Production with District Cooling

Over the past decades, combined heat and power production (CHP) has proven itself to be an efficient means of meeting both heat and power demands. However, high efficiency can be achieved with CHP plants when the heat load is sufficient, while lower-priority CHP plants must deal with the excess heat associated with power generation. This excess heat can be used for district cooling with absorption chillers. Although the absorption chiller is an efficient technology for using excess heat for cooling generation, its efficiency is very sensitive to driving hot water temperature. This paper provides a detailed analysis of how cooling generation in CHP plants using absorption chillers affects power generation and primary energy consumption. This study is based on the operational parameters of the Mustamäe CHP plant (Tallinn, Estonia) and the cooling demand of the Tehnopol science and business campus and proposes a sufficient cooling production capacity based on the estimation of the campus’ cooling demand. Additional cooling production opportunities to meet district cooling demand are discussed and compared in this paper in terms of primary energy savings and economic profit. The study finds that for the effective use of CHP excess heat and efficient cooling production, the use of an 0.8 MW absorption cooler and 11.6 MW heat pumps is recommended. This system would use 1.9 times less primary energy for cooling generation than local cooling.

Hybrid concentrator photovoltaic/membrane distillation system for potable water production using new fabricated PS/ZIF_L membrane

A hybrid system is proposed to use solar energy as a heating source for the membrane distillation unit. Concentrating photovoltaic needs an efficient cooling system to manage the excess thermal load. Two microchannel heat sinks were proposed to keep the cells from thermal degradation and simultaneously transfer the excess thermal energy to the membrane distillation unit. The results showed a maximum coolant outlet temperature of 59 °C, which is adequate for the membrane distillation unit. A new composite electrospun nanofibrous membrane was successfully synthesized to reduce unfavorable membrane wettability. First, ZIF-L nanoparticles were synthesized and characterized to prove successful preparation, then used as a nanofiller with polystyrene as the polymer membrane matrix for the first time. SEM, XRD, FTIR, static water contact angle, membrane thickness, and porosity were introduced to prove nanofillers' successful preparation and encapsulation. The antiwetting phenomenon was proven by the measured contact angle of 160°. Furthermore, the fabricated membrane was tested experimentally on a lap scale direct contact membrane distillation unit with a productivity of about 4 kg/m2 h and 18 ppm water quality at 55 °C hot water temperature. Also, the introduced membrane outperformed the productivity of the commercial PVDF membrane at all examined operating conditions.

Comparative analysis of fluid flow in mini channel with nano fluids and base fluid

Comparative study is carrying out between nano fluid Al2O3 + CuO + ZnO + H2O and water as solitary fluid through experimental and simulation result. The outcome of nano fluid and solo base fluid H2O flowing in middle rectangular mini channel with or without insert were admit, for study the conduct of fluid flow and heat exchange features. During composing of nano fluid 0.05%-0.1% volume fraction, 10–20 nm size nano particles were mixed with 0.5 ml CTAB surfactant. Experimentation were manage for different operating parameters under counter flow conditions, where nano fluid is flowing inside mini channel of 2 mm diameter with flow rate 0.0001562 to 0.006255 ml/min and hot water is flowing inside the concentric tube of 3.6 cm diameter with flow rate of 0.000782 ml/min. The operating temperature of nano fluid and hot water were 308 K and 323 K. As per obtained results, the proposed composition of nanofluid showed better performance than normal water due to better thermal conductivity and extra molecular area gain in nanofluid due to addition of nano particle with base fluid, where as better optimum results were observed in case of rectangular mini channel with macro insert compared with other geometry because of rich turbulency gain and extra exposed area due to macro insert.

Development and performance evaluation of novel silica gel-coated heat exchanger with high durability and conductivity to improve adsorption water treatment

Adsorption water treatment (AWT) has received considerable attention because it can be used to produce freshwater using low-grade heat sources. Furthermore, owing to its nearly consistent desalination performance and high-water recovery rate (>80 %), it has a high potential for use as a minimal liquid discharge process. However, a low freshwater production yield per unit volume of the AWT system is observed because the AWT system uses an adsorbent-packed heat exchanger (APHE), which has a high thermal resistance. In this study, the development and performance evaluation of a novel adsorbent-coated heat exchanger (ACHE) with high durability and conductivity is presented to enhance the heat and mass transfer rates during the adsorption and desorption processes. Binders and spray coating methods are utilized to achieve a uniform coating thickness and highly durable ACHE, and the adhesion strength is investigated using a pull-off test. The physical properties of the composite adsorbent are then examined using argon and water vapor adsorption isotherms, and the thermal conductivity is determined using the transient plane source method. Finally, the performance of the AWT process is evaluated considering the hot-water temperature and cycle time and achieves a significant superiority in the ACHE compared with the APHE.

Investigation of the cascade type of hybrid adsorption-vapor compression chiller

A numerical analysis was performed on a hybrid cooling system consisting of an adsorption chiller (ADC) and a vapor compression chiller (VCC) operating in a cascade mode. The system was evaluated for its overall performance and energy savings compared to standalone ADC or VCC cooling systems. The ADC utilizes an RD silica gel/water working pair, while the VCC uses R410A refrigerant. The cooling strategy involves the ADC providing cooling for loads up to 10 kW, with the VCC supporting the ADC when cooling loads exceed 10 kW, up to 15 kW. MATLAB and Refprop were used to model the system, and the results were consistent with prior research. The study examined the effects of adsorption cycle time, hot water temperature, cold water temperature, adsorbent particle size, and intermediate mass flow rate. Additionally, the performance of different adsorbents, including CaCl2 bound to mesoporous silica (SWS-1L) and Ferro-aluminophosphate (FAM-Z01), was compared to RD silica gel. The hybrid system reduced compressor work by 94.57% and 97.69% compared to conventional VCC when the hot water temperature was set to 90 °C, and cold water temperature was set to 26 °C, respectively. The hybrid system achieved the highest energy savings and overall coefficient of performance, with SWS-1L achieving a 91.37% energy savings and a 6.71 coefficient of performance. Therefore, the cascade-type hybrid cooling system is a superior alternative, particularly for cooling loads ranging from 10 kW to 23 kW, offering significant energy savings compared to conventional VCC systems.

Experimental studies on solar multi - effect sea water desalination system

A multi - effect desalination (MED) system with a capacity of 10 m3 has been designed, fabricated, erected and experimented to convert sea water into potable water using solar energy. Steam is flashed initially in the flash chamber of the desalination plant, using hot water from a solar flat plate collector field and is fed to the first stage of the multi-effect evaporator. The average hot water temperature realised from the collector field is 75°C. In the multi-stage evaporator, sea water is sprayed parallelly to vacuum pressure to produce water vapour and simultaneously condense the water vapour flashing through the tube from the flash chamber / previous effects. The brine and condensate is carried to the last stage of the multi-effect desalination (MED) system by utilizing monometric head. It is observed that during the experimentation, the maximum temperature difference between inlet and outlet of the condenser cooling water is 13°C. The ejector is used to maintain the vacuum pressure during the operation of MED system including flash chamber. Experimental studies on the MED system is carried out to understand the performance as well as thermal behaviour of the system using exclusively solar energy.

Multi-objective study on an innovative system for domestic hot water production: A pilot building in Southern Europe

The present study deals with a multi-objective analysis of an innovative decentralised system to produce and store domestic hot water (DHW), emphasising on the combined effects of the technological aspect, control strategy and user’s behaviour. The proposed system, by relying on thermal energy storage, decouples energy production and demand while shaves peaks in the energy demand and, at the same time, provides more autonomy to users through local storages. To identify subtle interactions in components of DHW system, dynamic simulations are carried out by establishing a coupled TRNSYS-MATLAB code, calibrated and validated by experimental measurements. The energy analysis implies that the proposed system cuts the required annual electrical energy in half, of which up to 82% of needed primary energy is supplied from renewable sources, compared to previous electrical-decentralised system. The optimisation of the results through applying control strategies indicates that adopting a three-time charging scheme is advantageous in terms of providing a more stable temperature profile as well as a higher hot water temperature. Compared to an available-by-demand operation, this scheme reduces the required total annual electricity by 5.2 % and enhances total thermal loss from components up to 4.0%. Furthermore, a sensitivity analysis on the results emphasises the striking role of the user behaviour in electrical energy consumption either via draw-off temperature or adjusting the pre-defined temperature for activation of the built-in auxiliary heater.

Design, optimization and economic viability of an industrial low temperature hot water production system in Algeria: A case study

Solar energy has a great potential in many areas of industrial activity in Algeria. This is because most of Algeria has high levels of sustainable solar insulation. Unfortunately, few industries use solar energy for hot water generation, but some industrial processes require hot water at temperatures that can be easily obtained from solar thermal panels. This paper presents a case study to investigate the technical and financial feasibility of a solar-powered industrial agro-processing system in Algiers. Based on the solar collectors connection type for which the economic feasibility study was carried out, an appropriate design of the system was determined. The latter was actually done by analyzing the levelized cost of energy savings. The design of the thermo-solar process is carried out based on F-chart method with a new approach by integrating the incidence angle modifier and of using real and experimental data requirements to determine realistic achievable performance of the solar process. The results showed that, in comparison to the currently used electrical system, the electrical energy savings achieved by the solar-powered system make it an economically viable option with a solar coverage rate of 80%. The investment depreciation balance shows that the use of such a thermal solar energy system will be more competitive than fossil fuels system if the price of electricity in the country increases from 0.048 to 0.075 €/kWh.

Thermo-economic optimization design of steam-water organic Rankine cycle with splitting flow

Aiming to address the potential scenario of waste heat recovery from a steam-water dual heat source, this paper proposes the thermo-economic models of split-flow dual-loop organic Rankine cycle (SFD-ORC) and split-flow triple-loop organic Rankine cycle (SFT-ORC) systems. The particle swarm optimization (PSO) algorithm is employed for single-objective optimization of the systems, with the goal of maximizing the net power output. The non-dominated sorting genetic algorithm-II (NSGA-II) algorithm is used to find the Pareto frontier by considering both the maximum net power output and the lowest cost of electricity production. The multi-objective optimization parameters are evaluated using the entropy weight method and TOPSIS method. The results show that the hot water split ratio and hot water outlet temperature of the high-pressure loop are higher in multi-objective optimization compared to single-objective optimization. The net output power of the SFT-ORC system after single-objective optimization can be up to 7.9% higher than that of the SFD-ORC system. From an economic perspective, it is recommended to use the SFD-ORC system at a hot water temperature of 85 °C–90 °C. In order to enhance the economic performance of the system, the steam outlet pressure should be as low as possible within the allowable range.

Spatial distribution of radon contamination in hot springs water and its cancer and non-cancer risks in the Hunza-Nagar valley, Pakistan.

Radon (222Rn) is a ubiquitous radioactive gas and could threaten human life due to its potential for cancer and non-cancer risks. This study examined the measurement of 222Rn concentration and associated health risks in the hot springs of Hunza-Nagar valley. For this purpose, the hot springs water of Hunza and Nagar districts and the background sites were analyzed for 222Rn concentration using the RAD7 detector (Durridge Company, USA). The average concentrations of 222Rn were 46.1 ± 0.94, 65.3 ± 0.45, and 5.47 ± 0.25Bq/L in the Hunza district, Nagar district, and background sites, respectively. Results showed that 222Rn concentrations of hot springs water were multifold higher than the background sites. 222Rn concentrations for hot springs water in Hunza-Nagar valley had surpassed the maximum contamination level set by the US environmental protection agency (USEPA). Humans' annual mean exposure dose rates of various age groups were calculated for the estimated lifetime cancer risk (ELCR) and non-cancer risks. The total annual mean exposure doses from 222Rn in water (EwTotal) values were (187 ± 3.80, 265 ± 1.84, and 22.2 ± 1.02μSv/a) for infants (143 ± 2.92, 203 ± 1.40, and 17.0 ± 0.78μSv/a) children, and (138 ± 2.80, 196 ± 1.35, and 16.4 ± 0.76μSv/a) adults in the Hunza district, Nagar district, and background, respectively. Among the age groups of humans, infants showed a higher risk than others. Results showed that hot springs water consumption surpassed the world health organization threshold of 100μSv/y for chronic or non-cancer and USEPA 0.1 × 10-3 for ELCR risks.The concentration of 222Rn showed a positive correlation (> 0.68) with hot springs' water temperature and pH suggesting a common origin.

Design and experimental analysis of a shell and tube vapor generator for solar thermal vapor absorption refrigeration

The generator is a crucial component of absorption refrigeration system as it provides a major input to the system. The overall performance of the absorption system mainly depends on vapor generation rate in a generator. Various studies are available in the literature on LiBr-H2O vapor absorption refrigeration systems. However, all these studies are focused on the performance of high-capacity commercial systems. Further, detailed analysis and feasibility of generator designs is not well explored though it is an important component of the system. Thus, present novel study is aimed to provide the idea about generator design and performance for a low-capacity system useful for residential applications. The objective of the present work is to investigate the shell and tube heat exchanger as a vapor generator for a vapor absorption refrigeration system experimentally. A LiBr-H2O vapor absorption refrigeration system requires water separation from LiBr in the vapor generator. The vapor generation depends on the saturation temperature and pressure. In this study, a shell and tube heat exchanger is designed for a vapor absorption refrigeration system of 0.5 ton of refrigeration. The experimental investigations are carried out at different operating conditions to evaluate the unit's performance and define its suitability for low-capacity absorption refrigeration system. Considering the output temperature of hot water from the solar thermal collector (80 –90 ℃) and pressure restrictions on the vapor generation process due to the crystallization of lithium bromide, the presented heat exchanger design is evaluated for pressure ranging between −0.90 bar and −0.65 bar. The experimental evaluation revealed that the heat exchanger is the most effective when the inlet temperature is 80 ℃ at a flow rate of 3 L per minute, and the initial pressure is −0.65 bar, while it is least effective for −0.90 bar. Further, vapor generation is greatest at −0.90 bar and lowest at −0.65 bar. The given configuration is suitable for an absorption system of cooling capacity 0.16 to 0.3 TR, as it can supply the vapor at the required flow rate at a given saturation temperature and pressure suitable for the de-absorption of water from LiBr.