Experiments were carried out for a counter flow dehumidifier with random packing and LiBr solution when solution flow was 800—1600 L·h^-1 with inlet concentration and temperature of 49%—54%，and 28—41℃，respectively，and the air velocity of empty tower was 0.39—0.96 m·s^-1，inlet air humidity was 10—21 g·kg^-1.The performance of dehumidification was described by moisture removal and volumetric mass transfer coefficient.The impact of the solution and the air inlet parameters on the dehumidification performance were analysed.With an average volumetric mass transfer coefficient of 1.0 kg

This paper presents the online optimal control strategies for multiple-chiller plants in large buildings with enhanced robustness and cost efficiency，including optimization of chilled water supply temperature set-point，chiller sequencing control，optimal start control and electrical demand limiting control.The chilled water supply temperature set-point optimization aims to minimize the total energy consumption of chillers and chilled water distribution pumps.In the chiller sequencing control，three schemes are used to enhance its control robustness，including a data fusion scheme for improved reliability of building cooling load measurement，a simplified adaptive model of maximum chiller cooling capacity，and an online sensor fault detection and diagnosis（FDD）.In the chiller optimal start control，a model-based strategy is proposed for minimizing the energy consumption in the morning start period.The model-based optimal start control strategy considers both the recovery ability and the pre-cooling lead time as its optimizing variables.The peak demand limiting control strategy minimizes the monthly electricity bill by predicting a suitable monthly peak demand threshold and restraining the daily peak demand to the threshold.These control strategies are validated using the dynamic simulation of the central chiller plant in a high-rising building in Hong Kong.

The air-conditioning system using tetrebutylammonium bromide (TBAB) clathrate hydrate slurry (CHS) as cold storage material was designed and built.By measuring the system power consumption, temperature, flow rate and the pressure drop of the fluid, system COP was evaluated.The measured TBAB CHS thermal properties and the developed flow and heat transfer correlations in the authors’ former experiments were validated by the results of the system operation.The tests confirmed the reliability of this system, however, further improvements are still proposed based on the test results and the corresponding discussion.

The air-conditioning mathematical model of temperature control in the testing room of an air enthalpy-difference testing-platform is presented, which can be described by a first-order-plus-dead-time model.The parameters of air-conditioning processes vary due to the changes in the operation conditions, which can lead to degradation of performance and instability of the control loop while using conventional PI controllers .A fuzzy PI adaptive controller with intelligence is proposed and applied to the air-conditioning system.In the control scheme, fuzzy control and PI control are combined together organically.The increment of the PI controller parameters can be adjusted online by fuzzy rules according to practical control experiences.To evaluate the control performance of the controller in the air-conditioning system, it is compared with a conventional well-tuned PI controller.Simulations results indicate that the proposed control method has better performance than the latter.

An organic Rankine cycle driven by the cold energy of liquefied natural gas(LNG) and waste heat in exhaust gas was established to improve energy efficiency.Several organic Rankine cycles using different working fluids were simulated with the process simulator HYSYS.Results show that propane is the most suitable working fluid.The evaporation temperature of working fluid has a significant effect on net power output per unit mass of LNG and exergy efficiency.More exhaust gas flow rate and higher exhaust temperature can contribute to improve system performance.A suitable condensation temperature is necessary to ensure the net power output per unit mass of LNG in a reasonable range, and also can improve system exergy efficiency.

A solar powered ice-maker system, which included ice-maker, parabolic tough collector (PTC), thermostatic oil bath and so on, was designed and established.The adsorption ice-maker used CaCl₂/activated carbon (AC) as compound adsorbent while ammonia as adsorbate.The thermostatic oil bath was used to simulate the different grades of solar energy, which can be obtained under different weather conditions, to supply energy for adsorption ice-making.Experiment results showed that the solar coefficient of performance (COP) of the ice-maker ranged from 0.09 to 0.14 and the daily ice production ranged from 10 kg to 28 kg, when the driving heat temperature ranged from 110℃ to 155℃.

Flow uniformity is an important index in many research fields.In order to use directly numerical simulation results to analyze flow uniformity quickly, abolish the data collection points setting and simplify computation process, a new correlation based on area-weighted and mass-weighted average velocity was proposed through the uniformity analysis of 24 velocity distribution under the circumstance of three velocity change at assumed cross-section in this study.The correlation and the corresponding formula in the literature were respectively adopted to calculate the uniformity of 24 velocity distribution at assumed cross-section.The results showed that the evaluating results by the correlation were basically consistent with that by the formula when velocity distribution uniformity was over 60%, the evaluating results by the correlation were worse than that by the formula when velocity distribution uniformity was less than 60%.However, the flow that uniformity is worse always need to further improve its structure, the uniformity was just providing a basis for improvement.Therefore, the results by the correlation have fully reference value for analysing flow uniformity.Finally, take supplying air of a metro vehicle air-conditioning duct as an example, the above theoretical analysis results were further verified, which confirmed the rationality of the correlation reflecting flow uniformity.

Airflow generated by fabric air dispersion system (FADS) in penetration mode was visualized, and the distribution of pressure along the radial and air flow direction inside FADS was quantificationally analyzed.Experimental results show that airflow disperses out from porous fiber, and moves downward in very low speed, and there exists eddies surrounding the diffusion zone.In addition, the static pressure along the radius direction inside FADS reduces with small gradient and the corresponding total pressure seldom changes.Furthermore, the total pressure along the flow direction reduces gradually, and the corresponding static pressure increases with small gradient, the maximum value occurs at the end of FADS.

According to the principle of cascade use of energy, a recycling air conditioning system combining water thermal storage and phase change material (PCM) thermal storage was presented.A water thermal storage and a phase change thermal storage are installed in series before the air cooled condenser.Superheated refrigerant vapor from the compressor flows through the phase change thermal storage first, the heat of superheating being stored in it, and then flows through the water thermal storage and exchanges heat with the water.Part of latent heat of condensation is stored in water thermal storage.The result of the experiments indicated that the heat recovery air conditioning system can effectively recover 19.6% of the condensing heat. When air conditioning does not work, the hot water produced under smaller flow rate is above 40℃ and produced under greater flow rate is above 40℃ also with air conditioning working. It not only can save energy but also satisfy the hot water demand of users.

In order to balance the supply and demand of energy spatially and temporally, and to enhance efficiency of energy utilization, this work presents a novel chemisorption cold storage device driven by low grade thermal energy.This device employed MnCl₂/NH₄Cl as working pair, which were individually mixed with expanded graphite as compound sorbents, and ammonia as refrigerant.Experiments were conducted under different ambient temperature ranging from 20℃ to 35℃, thus the cooling capacity was obtained by measuring the mass of the ice transformed from water and was calculated as 475 kJ·kg^-1 of NH4Cl salt during 3 hours’ operation, however, the effective cooling production accounted for 25%—42%.The average specific cooling power was 43 W·kg^-1 of NH₄Cl salt.This device achieved two refrigeration temperature levels: -1—6℃ and -16—14.5℃ respectively for two relative independent zoons inside the device.Reducing the metallic components,enhancing the transfer properties and insulation performance of the device are the key subjects of further optimization work.

Formerly the evaporative cooling technology is used to make cold air and the high temperature cold water is made only by the pure evaporative cooling method.But the temperature cold air and water is easy to be affected by outdoor condition, so that it is difficult to assure indoor temperature and humidity requirement.This paper introduced some types of evaporative cooling chillers.Then a new kind of high temperature chiller is proposed to provide high temperature cold water for manifested heat terminal.And the  advantages and the application prospect of this chiller are compared with the present several kinds of high temperature heat sink merit .

To solve the idle problem of chillers and the frosting problem of air-source heat pumps in winter, a heat pump system based on heat-source tower was proposed.The structure and work process of this system were analyzed in detail, and an experimental device of heat-source tower heat pump was built.The heating experiments with the variation temperature difference of solution between the heat-source tower inlet and outlet were carried out.The experimental results showed that the heating capacity of the heat pump and COP were decreased, the power consumption of compressor changed little, and the difference between air temperature and evaporating temperature was enlarged when the temperature difference of solution between the heat-source tower inlet and outlet increased. The COP of heat pump declined from 3.02 to 2.72, and the difference between air temperature and evaporating temperature enhanced from 7.64℃ to 11.96℃, when the environment temperature was -1.2℃,and the temperature difference of solution between the heat-source tower inlet and outlet changed from 1.5℃ to 3℃. The operation of this system was stable and reliable during the whole experiment, and the frosting problem was avoided.The results indicate that the heat-source tower heat pump is a very promising scheme for heating/cooling.

According to the energy-level features of cold energy from gasification station, not only the mode of utilizing such cold energy at refrigerated warehouse was analyzed, but also the various system process flow and corresponding features of such cold stores was compared in this paper.Under certain assumed conditions, the technological and economic analysis of the third flow mode was made by taking a gasification station with the gas supplying capability of 4×10⁷ m³ per year as an example.Results indicate that under a 33% cold energy reclaim ratio of the refrigerated warehouse, the annual profit from available reclaimed cold energy of the gasification station is 6.113 million CNY, and the operation cost of the refrigerated warehouse under this mode is low.Therefore its payback period is no more than a year and economic benefits significant.

The universal mathematical model of engine was established by the testing model of engine, and the economical operating zone of engine was presented and described.Based on the testing data of a refitted engine, the universal performance curve of the given engine had been obtained, and then economical upper bound and lower bound of the special economical operating zone of engine were demarcated, as well as the optimal torque curve.Analysis showed that in the special economical operating zone of engine, the speed range was about 2300—3850 r·min^-1, the torque range was about 17.5—27.9 N·m, and output load region 5—9.5 kW, also the average thermal efficiency could be over 0.25, but the highest thermal efficiency of the engine could not exceed 0.285.

Compared with conventional packed regenerator, internally heated regenerator is proposed to ac-hieve better regeneration performance.This study emphasized on both regeneration rate and regeneration thermal efficiency to evaluate the performance of both regenerators.The results indicated that internally heated regenerator could not only increase the regenerate rate, but also exhibit higher energy utilization efficiency.Different from adiabatic regenerator, internally heated regenerator can provide comparable regeneration efficiency and regeneration rate at low desiccant flow rate, so it should be a good alternative to avoid carryover of desiccant droplets.Higher air flow rate would result in a deduction of regeneration thermal efficiency although achieving higher regeneration rate.Suitable flow rate of the air should be considered carefully in liquid desiccant regeneration.The internally regenerator could have considerable prospect in liquid desiccantair conditioning application.

Although lithium bromide absorption chillers（LBAC）are widely used to provide thermal comfort by utilizing waste heat，they suffer from low efficiency.This paper presents an experimental investigation on a novel reformed LBAC based on the absorption principle of the duality solution in the sub-steady equilibrium state.This increases the pressure in the absorber and decreases temperature in the generator，resulting in doubling the refrigeration capacity of the LBAC.The COP of the system improves by 1.5 times when the absorption pressure increases from 1.2 kPa to 2.2 kPa.

A model for the heat transfer of  vacuum insulation panel（VIP）and polyurethane foam（PU）multiple-insulator applied to freezer is established and the relationship between the heat flux and thickness of VIP under different total thickness of the multiple-insulator is analyzed.Five curves of heat flux versus thickness of VIP corresponding to five kinds of total thickness of multiple-insulator are presented through simulation.The energy-saving effect and economic benefits from the VIP+PU multiple-insulator applying to freezer are further analyzed and then the optimal thicknesses of VIP in multiple-insulator and its corresponding invest recall-period under different total thicknesses are obtained.It is revealed that all the optimal thicknesses of VIP nearly have the same value of 0.01 m.The shortest invest recall period for the application of the multiple-insulator instead of pure PU insulator to freezer is 3.7 years.

Because of the large size of the new type accelerated loading system, the accurate simulation of air temperature, road temperature and roadbed temperature are the key points and also difficult points for designing the system.By using the software Fluent, this paper simulated the running conditions of the everfrost simulation system and obtained the following results.When the thermally conductive surface had become a flat surface, under the condition of the thickness of the pipe layer was 30 cm, the largest pipe pitch was 40 cm, the position of the thermally conductive surface was independent of the roadbed materials.When the conditions of temperature and speed of cold wind, the temperature and the speed of secondary refrigerant and the diameter of the pipes were all fixed values, the optimal tube pitch was 25 cm, which was independent of the roadbed materials.When the conditions of temperature and speed of cold wind, the temperature and the speed of secondary refrigerant and the diameter of the pipes were all fixed values, when the temperature inside the roadbed had reached the requirement, the total energy cost was independent of the pipe pitches but was relevant to the roadbed materials.

Two typical types of CO₂-NH₃ cascade and NH₃ two stage compression refrigeration processes were designed and calculated.The key parameters of the two processes were compared, and the heat flow distributions of heat exchangers were also analyzed, as well as parameters optimization of the NH3 refrigeration system.The results show that in terms of evaporation temperature at -45℃, the total power consumption of compressors and NH₃ flow of the CO₂-NH₃ cascade process are less than that of the NH₃ process.But there is massive refrigeration capacity at medium temperature in NH3 process, so the COP of NH3 process is higher than that of CO₂-NH₃ process.The difference in temperature of two phase liquids in the condensation-evaporator of cascade system is less, and that in the midst cooler of NH₃ system is larger.Along with the ascending exhaust pressure of low-pressure stage compressor and the descending midst temperature, the total power consumption of the NH3 process of two stage compression will be downtrend.

New air bearing-rotor system is applied to technological rebuild of the shaft system in air cycle refrigerator which uses the conventional rolling bearing-rotor structure.Experimental investigations focused on the characteristics of the rotating speed of the refrigerator.The results show that the margin of stability operation，service life and cooling capacity were greatly increased.