Showing papers on "Thermal expansion valve published in 2018"
TL;DR: In this article, the effects of hot-water outlet temperature, compressor discharge pressure, compressor rotation speed, and expansion valve opening on the ejector and overall system performance were investigated for tap water outlet temperatures ranging from 50 to 90°C.
75 citations
TL;DR: The Benchmark proposed for the 3rd IFAC Conference on Advances in Proportional-Integral-Derivative Control (PID’18) held in July 2017 is described, to test their recent developments in the design of PID controllers on a challenging control problem.
40 citations
TL;DR: The performance of an ejector refrigeration system (ERS) with R134a ejectors was investigated experimentally in this article, where the authors found that the change of the ejector operational mode caused by varying the operating and geometric parameters of ejector has significant impact on ejector performance.
38 citations
TL;DR: In this article, double-pipe heat exchanger/condenser setup was used in an air conditioning system serving a 45m 3 balanced calorimeter of 2.24kW heat load.
37 citations
TL;DR: In this paper, a visualization study for a compact copper-water loop heat pipe with flat evaporator was carried out under gravity favorable mode in order to fully investigate the two-phase flow characteristics inside a LHP.
36 citations
TL;DR: In this article, a dual-loop bi-evaporator vapor compression refrigeration cycle is proposed to meet the demands for freezing and air-conditioning applications which can be employed in building sectors.
34 citations
Patent•
29 Nov 2018
TL;DR: In this article, an air-conditioning machine consisting of a refrigeration circuit Q where a coolant is circulated through a compressor 31, a condenser, an outdoor expansion valve 34 and an evaporator in series is presented.
Abstract: PROBLEM TO BE SOLVED: To provide an air-conditioning machine capable of appropriately cleaning an indoor heat exchanger.SOLUTION: An air-conditioning machine 100 comprises: a refrigeration circuit Q where a coolant is circulated through a compressor 31, a condenser, an outdoor expansion valve 34 and an evaporator in series; and a control section which controls at least the compressor 31 and the outdoor expansion valve 34. One of the condenser and the evaporator is an outdoor heat exchanger 32 and the other is an indoor heat exchanger 12 having a temperature sensor to detect a temperature of the indoor heat exchanger 12. The control device causes the indoor heat exchanger 12 to function as the evaporator and stops a freezing process to freeze the indoor heat exchanger 12 after the lapse of a predetermined first period since the freezing process is started.SELECTED DRAWING: Figure 3
32 citations
TL;DR: In this article, a solar-driven ejector-cascade heat pump cycle is proposed to improve the performance of an air-source heat pump under low ambient temperature, in which an ejector sub-cycle takes R134a, R1234yf or R141b as working fluid and a vapor compression sub-cycler uses R12 34yf as a refrigerant.
31 citations
TL;DR: In this paper, the authors presented a novel framework for designing and optimal scheduling of an air source heat pump based industrial continuous heat treatment furnace (ICHTF) which is driven by a solar Stirling engine and a wind turbine.
27 citations
TL;DR: In this paper, the effects of several types of faults on air conditioners and heat pumps have been studied in many laboratory experiments, and the independent variable (fault intensity) and each of the dependent variables are normalized to show the trends in a generalized fashion.
Abstract: The effects of several types of faults on air conditioners and heat pumps have been studied in many laboratory experiments. All available data have been gathered, and the independent variable (fault intensity) and each of the dependent variables (fault impacts) are normalized to show the trends in a generalized fashion. Relationships are provided wherever there are sufficient results. Most of the significant fault types are included (except refrigerant charge variation, which was discussed in Mehrabi and Yuill (2017)): condenser heat transfer (CA), evaporator heat transfer (EA), liquid line restriction (LL), compressor leakage (VL), and non-condensables in the refrigerant (NC). Relationships are presented separately for fixed orifice and thermostatic expansion valve equipped systems. The variation level in the results indicates that in many cases, the generalized relationships provide reasonable predictors of fault effects on systems for which laboratory test results are unavailable. These relationships provide the first generalized fault effect models for air conditioners and heat pumps.
25 citations
TL;DR: In this article, the effects of using expander and Internal Heat Exchanger (IHE) have been investigated numerically in a horizontal DirectExpansion Geothermal Heat Pump (DX-GHP), based on energy and exergy analyses.
TL;DR: In this paper, the effects of R290 refrigerant charge influences on a split air conditioning system with different throttling devices including capillary tube, thermostatic expansion valve, and electronic expansion valve (EEV) are experimentally investigated alongside with the indoor temperature, outdoor temperature and indoor air volume flow rates effects.
TL;DR: In this article, a novel exergy-based charge optimisation technique is proposed instead of coefficient of performance (COP) based method for a mobile air conditioning system, and the exergy destructions in each of the components in the system as a function of compressor speed and refrigerant charge level were estimated based on experimental data.
Abstract: In this paper, a novel exergy based charge optimisation technique is proposed instead of coefficient of performance (COP) based method for a mobile air conditioning system. The exergy destructions in each of the components in the system as a function of compressor speed and refrigerant charge level were estimated based on experimental data. It was found that the COP of the system decreases as the compressor speed increases, while the total exergy destruction in the system increases. The exergetic analysis of performance data showed that the percentage loss in the compressor, evaporator, condenser and thermostatic expansion valve lies in the range of 59.88–69.9%, 17.53–25%, 7.80–16.36% and 3.05–15.73%, respectively. Based on COP, the optimum charge varied with respect to compressor speed. The exergy based optimisation is found to be more reliable and consistently yielding a single optimum charge of 620 g irrespective of the compressor speed. The maximum exergetic efficiencies at 620 g were 43.32% and 38.15% for 900 rpm and 1800 rpm respectively.
TL;DR: In this article, two types of expansion valve (thermostatic/electronic) were compared in steady and transient state to tackle sleeping evaporators and benefit from refrigerant maldistribution.
Abstract: With the arrival of electrified vehicles, the air-conditioning system has to be reconsidered. Battery cooling management system and high level of comfort for passengers make the single evaporator air-conditioning system a multi-evaporator one. In a multi-evaporator air-conditioning system, evaporating pressures are equal in each evaporator so that evaporators are coupled dynamically. However, the demand in cooling capacity and temperature target can vary from each other. For an operating point with a first evaporator working at high load and a second at low partial load, thermal interaction can occur from the superheated refrigerant coming from a first evaporator to the outlet of a second evaporator. This phenomenon makes the second evaporator sleeping since its expansion valve bulb misreads the superheat and closes. Furthermore, sleeping evaporator looks like an extreme case of refrigerant maldistribution in the evaporator. Refrigerant maldistribution is then investigated to show some drawbacks and advantages multi-evaporator air-conditioning systems (MEAC) have to face or can benefit by comparing two types of expansion valve: thermostatic and electronic ones. In this paper, sleeping evaporator and refrigerant maldistribution phenomena are experimentally investigated in order to propose in the future a robust control of an automotive MEAC. A test bench was built to compare two types of expansion valves (thermostatic/electronic) and study their behaviours in steady and transient state to tackle sleeping evaporators and benefit from refrigerant maldistribution.
TL;DR: In this article, the effects of external perturbations of pump speed, expansion valve opening and engine conditions on dynamic performance of the CTPC systems were investigated with step changes, and the results showed that both a basic CTPC system and a CTPC with a recuperator (R-CTPC) behave as a second-order underdamped system with the perturbation of pump speeds and expansion valve openings.
TL;DR: In this paper, a single-effect absorption refrigeration system that uses LiBr-water solution and engine exhaust gas is investigated, and the results show that the system could work with an engine speed of 1200-1400 rpm.
Patent•
28 Dec 2018
TL;DR: In this paper, the utility model provides an air conditioning system that relates to the electric automobile technical field, which includes permanent magnetism sync pulse compression machine, condensers, dry reservoir, the expansion valve, an evaporator, power module and control module.
Abstract: The utility model provides an air conditioning system relates to the electric automobile technical field. This air conditioning system includes permanent magnetism sync pulse compression machine, condensers, dry reservoir, the expansion valve, an evaporator, power module and control module, power module includes pre -charge circuit, main switch ware and converter, main switch ware and pre -chargecircuit, the equal electricity of a converter and a vehicle mounted power is connected, pre -charge circuit is connected with converter and the equal electricity of the vehicle mounted power, permanent magnetism sync pulse compression machine is connected with converter and the equal electricity of control module, permanent magnetism sync pulse compression machine is connected with the condenser,the condenser is connected with dry reservoir, dry reservoir is connected with the expansion valve, the expansion valve is connected with the evaporimeter. The utility model discloses an air conditioning system has higher work efficiency, energy -conserving benefit and stability.
TL;DR: In this paper, a prototype CO2 MAC system, consisting of a CO2 electrical compressor, CO2 parallel flow microchannel heat exchangers, and an electrical expansion valve, was developed and tested.
Abstract: CO2 (GWP = 1) is considered as a promising natural alternative refrigerant to HFC-134a in mobile air conditioning (MAC) applications. The objective of this study is to investigate the cooling performance characteristics of a CO2 MAC system. A prototype CO2 MAC system, consisting of a CO2 electrical compressor, CO2 parallel flow microchannel heat exchangers, and an electrical expansion valve, was developed and tested. Factor analysis experiments were conducted to reveal the effect of outdoor temperature on the cooling performance of this CO2 MAC system. Compared with a conventional R134a MAC system, the prototype CO2 MAC system achieved comparable cooling capacity, but had COP reductions of 26% and 10% at 27 °C and 45 °C outdoor conditions, respectively. In addition, based on refrigerant properties, theoretical cycle analysis was done to reveal the impact of evaporator, gas cooler and compressor, on the system cooling performance. It is concluded that the increase of overall compressor efficiency or the decrease of gas cooler approaching temperature could greatly improve the COP of this CO2 MAC system.
TL;DR: In this paper, a modified refrigeration cycle (MRC) using refrigerant mixture R170/R290 was proposed for applications in low-temperature freezers, where an additional recuperator and expansion valve were set between condenser and separator to realize phase separation at an intermediate pressure.
Abstract: In this study, a modified refrigeration cycle (MRC) using refrigerant mixture R170/R290 was proposed for applications in low-temperature freezers. Different from traditional auto-cascade cycle (ARC), additional recuperator and expansion valve are set between condenser and separator to realize phase separation at an intermediate pressure. The MRC can significantly improve volumetric refrigeration capacity (qev) and the coefficient of performance (COP) especially in low evaporating temperature condition. As evaporating temperature is set at −60°C, using MRC system can acquire 18% and 35% COP and qev improvements, and the compression ratio in MRC reduced 23% in comparison to ARC. In general, decreasing both separating temperature and quality of condenser outlet will benefit the performance of MRC. Besides, there exist an appropriate mixture quality at evaporator outlet to obtain the best COP and qev under the given condition.
TL;DR: An exergy/energy analysis of VRF technology is presented to address the effect of refrigerant flow as well as the cooling-air flow rates on the electric energy saving in the hot and humid zones and showed that refrigerant R-410a would be the second most efficient refrigerant, after ammonia, for such systems.
Patent•
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TL;DR: In this article, a seat air conditioner that is able to effectively use heat generated by a heat absorption part and a heat dissipation part, in order to adjust temperature is presented.
Abstract: PROBLEM TO BE SOLVED: To provide a seat air-conditioner that is able to effectively use heat generated by a heat absorption part and a heat dissipation part, in order to adjust temperature.SOLUTION: A seat air conditioner 1 is disposed between a seat surface part 51 of a vehicle seat 50 and a floor surface F of a vehicle chamber, and accommodates a refrigeration cycle and a blower in a housing 10. The refrigeration cycle has a compressor, a condenser, an expansion valve, and an evaporator. Air blown by a blower is heated by the condenser to create warm-air current WA and is cooled by the evaporator to create cold-air current CA. Warm-air current WA and cold-air current CA are supplied to each of a main duct 21, a duct 23 for a leg, an upper duct 25, and a lower duct 27, which are arranged in the seat 50, via an air-conditioning current supply part. Hot-air current WA and cold-air current CA are blown, via the main duct 21 and so on, to different parts of an occupant seated on the seat 50.SELECTED DRAWING: Figure 9
Patent•
12 Jan 2018
TL;DR: In this paper, a heat pump water heater consisting of a water heater shell, an evaporator, a condenser, a compressor, a liquid storage device, a filter and an expansion valve are arranged on the left side of the inner part of the water tank shell.
Abstract: The invention discloses a heat pump water heater. The heat pump water heater comprises a water heater shell; an evaporator is arranged on the left side of the inner part of the water heater shell; evaporator heat exchange pipes are arranged inside the evaporator; an electric heating tape is arranged on the evaporator heat exchange pipes; a condenser is arranged on the right side of the inner partof the water heater shell; a compressor is arranged between the upper side of the condenser and the upper side of the evaporator; a liquid storage device, a filter and an expansion valve are sequentially arranged between the lower side of the condenser and the lower side of the evaporator; a water tank inner container is arranged on the right side of the water heater shell; a temperature detectorand a water level instrument are arranged on the two inner side walls of the water tank inner container correspondingly; an electric heating rod is arranged in the water tank inner container; an anti-freezing fluid inlet is formed in the side, connected to a water tank, of a circulating water pipe; and a hot water outlet and a cold water inlet are formed in the other side surface of the water tank. According to the heat pump water heater, the heating speed and the heat exchange efficiency of the water heater can be improved, frost cracks can be prevented in a low-temperature environment, and the service life can be prolonged.
TL;DR: In this paper, a green absorption ice-making system consisting of an air-to-air heat pump (AAHP) and a Stirling engine is proposed for large residential buildings.
Patent•
24 May 2018
TL;DR: In this article, the authors proposed a multi-room type air conditioner capable of improving indoor comfort at a thermo-off time in a heating operation, and improving energy saving performance.
Abstract: PROBLEM TO BE SOLVED: To provide a multi-room type air conditioner capable of improving indoor comfort at a thermo-OFF time in a heating operation, and improving energy saving performance.SOLUTION: In a multi-room type air conditioner in which an outdoor unit 100 having a compressor 1, an outdoor heat exchanger 3, flow channel switching means 2 for switching a connection destination of one end of the outdoor heat exchanger to a suction side or a discharge side of the compressor, and an outdoor expansion valve 4 disposed in a pipe connected to the other end of the outdoor heat exchanger, and a plurality of indoor units (20a-20c) having at least indoor heat exchangers (21a-21c), are connected by a gas connection pipe 8 and a liquid connection pipe 9, the plurality of indoor units include first flow rate control devices (23a-23c) connected to liquid connection pipe sides of the indoor heat exchangers to control a refrigerant flow rate, and second flow rate control devices (22a-22c) connected to gas connection pipe sides of the indoor heat exchangers to control the refrigerant flow rate.SELECTED DRAWING: Figure 1
TL;DR: The qualitative and quantitative comparison results between the MFAC schemes and the default PID controllers given in the simulation platform provided by the Benchmark PID 2018 demonstrate the effectiveness of the two designed controllers.
Patent•
04 Oct 2018TL;DR: In this article, the discharge pressure detected by a discharge pressure sensor is less than a predetermined pressure threshold value while a heating operation is performed, and the controller sets a maximum time for continuing a defrosting operation started by a start condition of the defrost operation being satisfied to be shorter than a threshold value.
Abstract: According to one embodiment, an air conditioning apparatus has one or a plurality of indoor units, an outdoor unit, and a controller. The one or plurality of indoor units have an indoor heat exchanger, and an indoor expansion valve in which a degree of opening is variable. The outdoor unit has an outdoor heat exchanger, a four-way valve, a compressor, and a discharge pressure sensor configured to detect a pressure of a refrigerant discharged from the compressor. When a discharge pressure detected by the discharge pressure sensor is less than a predetermined pressure threshold value while a heating operation is performed, the controller sets a maximum time for continuing a defrosting operation started by a start condition of the defrosting operation being satisfied to be shorter than a maximum time for continuing the defrosting operation when the discharge pressure is equal to or higher than the pressure threshold value.
TL;DR: Simulations results show that the robust controllers reacts quickly reference settings, despite the non-measurement of the disturbance variables and the dynamic coupling of the multi-variable system, compared to decentralised single PIDs proposed with the benchmark.
Patent•
26 Jan 2018
TL;DR: In this article, an intelligent temperature control system and control method for a power battery of an electric vehicle is presented, in which the requirement of accurate temperature control of an integral vehicular battery under various operating conditions is met, requirements of heating, temperature balance and cooling of the integral vehicle battery can be met according to an intelligent control algorithm.
Abstract: The invention relates to an intelligent temperature control system and control method for a power battery of an electric vehicle. In the control system, a water pump, a three-way valve, a battery cooler, a water heating PTC, a cooling water temperature sensor, a battery cooling water pipe and a water pump are in sequential connection to form a battery heating/cooling water circulation circuit; thewater pump, the three-way valve, a battery cooling component, the water heating PTC, the cooling water temperature sensor, the battery cooling water pipe and the water pump are in sequential connection to form a battery cooling fan liquid cooling circulation circuit; a compressor, a pressure sensor, a condenser, an electromagnetic expansion valve, a battery cooler and a compressor are sequentially connected to form a refrigerating fluid circulation loop. A plurality of battery temperature sensors are connected with battery cells in a power battery. Compared with the prior art, the system andthe method have advantages that the requirement of accurate temperature control of an integral vehicular battery under various operating conditions is met, requirements of heating, temperature balanceand cooling of the integral vehicular battery can be met according to an intelligent control algorithm, and endurance mileage of the whole vehicle is increased while energy saving control is realized.
TL;DR: In this article, an optimized high-temperature heat pump (HTHP) adopting a new binary mixture named MF-1 as working fluid was designed and built for industrial waste heat recovery.
TL;DR: In this article, a sample of cold storage unit originally charged R404A is slightly modified without changing the unit structure and components but adding a parallel thermal expansion valve for charging R407A and R407F respectively.