Type Air Conditioner Research Articles

A fast prediction method for maximum APF of heat pump type air conditioners based on a single group of experimental data

The annual performance factor (APF) is a new performance index of heat pump type air conditioners (HPACs) based on multiple testing conditions which may result in orders of magnitude larger workload in the product development for enhancing the APF to be close to the maximal value. The development process can be accelerated if the maximum APF can be predicted. The purpose of this study is to present a fast prediction method with a high precision for the maximum APF of HPACs based on a single group of experimental data. The idea of achieving fast prediction is to establish a simplified lumped parameter model for the calculation of capacities and efficiencies of HPACs, and to present a simplified approximate APF correlation by eliminating all the intermediate parameters from the complicated APF equations defined in standards of HPACs. A group of experimental data is applied in the prediction model to improve the precision of the fast prediction method. Application of this method for a typical HPAC shows that the predicted maximum APF of the HPAC agrees well with the tested maximum APF, the maximum deviation of predicted capacities and efficiencies from the experimental data is within ±1.4%; and the duration of prediction for maximum APF is within 12 s on a typical personal computer, significantly saving the time of HPAC development.

A practical calibration method of the room type calorimeter for testing the energy efficiency of room air conditioner

The room type calorimeter is generally used as the energy efficiency measurement standard equipment in the air conditioner industry. However, the calibration procedure is not investigated. In this study, based on the empty-load situation of calorimeter, the calibration model is proposed in order to restrain the error of heat balance caused by long-term use. Besides, two new parameters, which are background value of indoor-side and outdoor-side, are presented in accordance with the calibration model. Experiments are designed to obtain these two parameters and three heat leakage coefficients of partition wall, as well as the calibration procedure and application method of the parameters are illustrated. The corrected calorimeter measures ten different window type air conditioners in one year. The results show that the absolute value of heat balance is less than 2% in the cooling capacity range of 2000W∼4500W and 1% in the range of 4500W∼7000W.

Study on Working Pairs of Sorption Type Air Conditioner for Electric Vehicles under Different Temperature Zones

The air conditioning (AC) system of electric vehicles (EVs) consumes a large part of electricity of on-board batteries and influences the continue voyage course seriously. The feasibility of sorption type AC for EVs has been verified theoretically to decrease this part of energy consumption. However, the choice of optimal working pairs based on local working conditions is not considered before, which can realize not only high efficiency but also the steady and reliable operation. Thus in this paper, different solid sorption working pairs used in sorption type AC under different temperature zones are studied. We utilized Rubotherm balance test unit to study the sorption properties of various working pairs (halide-ammonia) and selected candidate working pairs by Clapeyron equation and energy analysis. Results show that MnCl2 is the only choice for cold temperate zone (CTZ) and CaCl2 is optimal for warm temperate zone (WTZ), while the mixed double halide (MnCl2 and CaCl2) is recommended in other zones. In middle temperate zone (MTZ), the probability for performance dropping down is relatively large, thus the ratio (CaCl2:MnCl2) is recommended as 0.33-1 to take advantage of the stability property of MnCl2. While in Qinghai-Tibet plateau cold area (QTPCA, the special temperature zone in China), the ratio is chosen as 2–3 because only under the limiting condition reaction [Ca(NH3)8]VCl2 ⇔ [Ca(NH3)4]Cl2+4NH3 is invalid. Because the continued high environmental temperature will increase the probability of limiting condition, ratio of subtropical zone (STZ) is still selected as 2–3 while that of tropical Zone (TZ) is 1–2. Taking WTZ under summer condition as example, by using sorption type AC with CaCl2 as sorbent, the increment voyage course (IVC) over the practical voyage course with conventional compression AC system (PVC) ranges from 9.4% to 37.7% for different type of EVs, i.e. the continue voyage course is increased effectively. This work provides the guidance for choosing optimal working pairs for actual utilization.

On the Energy Efficiency of Indoor Air Conditioning

The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.

ANALYSIS OF ENERGY EFFICIENCY RATIO (EER) IN AIR CONDITIONER (AC) TYPE SPLIT

Cooling system is something that is already familiar to the people of Indonesia, both in domestic and industrial use. The cooling system functions to reduce the temperature of a room so that the temperature is as desired. The development of air conditioners is increasingly modern. The use of air conditioners (AC) is growing rapidly so that the CFCs produced affect the environment which can cause the ozone layer to be damaged and cause global warming. Therefore, there is a need for research related to the level of energy use. This study discusses the Energy Efficiency Ratio test to realize a government program that is family one number testing. Retrieval of data in this report is by testing the split type air conditioner, where this test aims to obtain an energy-saving star label on the air conditioner. All tests are carried out at the AC Chamber Laboratory located at the Center for Energy Conversion Technology (B2TKE) - BPPT which is a professional energy conversion testing center in Indonesia. The testing process is carried out in a structured way from initial checking of test materials, preparation of tests, testing to analysis of test results. Based on the test analysis results, it can be concluded that the Energy Efficiency Ratio (EER) value to get the energy saving sign star label and the test results obtained the Energy Efficiency Ratio (EER) value of 11,805 Btu / h and get a four star.

Thermal comfort of people from two types of air-conditioned buildings - Evidences from chamber experiments

Air conditioning has been basically generalized in buildings as the most effective means of cooling in South China; there are two common types of air conditioning: centralized air conditioning system and split-type air-conditioner. The present study recruited 60 healthy young people, half from buildings with centralized air conditioning system (CAC buildings) and half from buildings with split-type air-conditioner (SAC buildings), and exposed them to a wide range of temperatures (20–32 °C) and humidity (50% and 70%) in a climate chamber. The results showed that the mean skin temperature was significantly higher for subjects from the CAC buildings under the non-neutral conditions, whereas there were no significant differences for other physiological responses. The two groups of subjects reported the same neutral temperatures (26.8 °C and 26.6 °C) and thermal sensitivities (0.31 °C-1). The 90% thermally acceptable SET ranges were 24.8–27.4 °C and 24.4–30.1 °C for the two groups of subjects, and the range was narrower by 3.1 °C and the upper limit was lower by 2.7 °C for subjects from the CAC buildings. Thermal history containing intermittent and short-term high & low-temperature exposures in the SAC buildings is suggested to strengthen the occupants' thermoregulatory ability. The long-term experience with a more stable cool environment and the less perceived controls are expected to shape a higher thermal expectation of occupants in the CAC buildings. This study specifies the thermal requirements of people in the two types of air-conditioned buildings, and promotes the understanding of the impacts of thermal history and expectation on human thermal comfort.

Observational study on the cool breeze effect of a through wall type air conditioner

An air conditioning system has been developed that can select the operation pattern of a through-wall type unit (TWU) according to the air conditioning needs. There is a night-time cool breeze mode like natural ventilation using a fan in modes. The thermal environment and ventilation volume of office buildings can be greatly influenced by outdoor thermal conditions, and it is necessary to grasp the actual conditions. Therefore, in this research, the observational study of thermal environment and ventilation performance was conducted, and was compared and analysed with the simulation result. The cross-section wind velocity distribution was characterized in each area, but the wind velocity in the residential area was about 0.1 to 0.2 m/s, and no draft was seen immediately below the bypass duct outlet. It was almost in agreement with the simulation results. The ventilation performance survey revealed that the windward side was slightly difficult to ventilate. However, there was no big difference in the age of air depending on the location. Moreover, there was no significant difference in the total ventilation volume even if the outdoor thermal conditions were different. It was confirmed that the TWU had expected performance and stable ventilation performance was secured.

Mathematical and experimental analysis of the thermal effectiveness of an oscillating jet with side-to-side swing louvers in a cassette split type air conditioner

The impact of air supply control strategies (louvers movement) on indoor thermal environment were evaluated in this study. The temperature uniformity was evaluated by: (i) the air distribution performance index (ADPI) to determine the air diffusion performance in heating mode; (ii) the air draught rate (DR%) on the face to determine the local discomfort due to cold draught; (iii) the mathematically determined vertical temperature stratification in a room with Beta distributions. A comparison of the conventional type with three different oscillating type airflows (louvers swing angle ±20°, ±40° and ±60°) were experimentally analysed to determine appropriate air supply control strategies. The results indicated that Beta distributions could capture the overall trend of the oscillating airflow, to establish the acceptable thermal uniformity and higher thermal effectiveness. The oscillating airflow as generated by the side-to-side swing type delivery louvers mounted inside a cassette split type air conditioner could shorten heating time by 20% to attain room temperature from 9°C. The data reveal that oscillating airflow can provide a better thermal sensation to feeling warm in the heating mode at both ankle and neck level. The ADPI is approximately 85% in the occupied zone. The actual draught rates on the face ranged 0–35%.

Energy Efficiency and Safety for Wall Type Air Conditioner with Propane Refrigerant

Thailand has been used the R-32 refrigerant in air conditioner since 2016, while it has high global warming potentials (GWP = 675). A propane refrigerant (R-290) is introduced as a newly alternative refrigerant, due to the global issue on refrigerant substitution for friendly environment. It has GWP of 4, which is 169 times lower than R-32. In this study, the theoretical energy efficiency was analysed under the Thailand’s conditions at the saturated evaporation temperature of 10°C and the saturated condensation temperature of 47°C. However, the propane is highly flammable; therefore, the safety must be considered. The results showed that the coefficient of performance of propane was 5.54, which was 7% higher than R-32. The wall type air conditioner with propane refrigerant would be safe from fire if it was installed at a height higher than 1.8 m above the floor level and the floor area was larger than 17 and 23 m2 for air conditioner cooling capacity of 3375 W and 5000 W, respectively.

低コスト版個別分散型空調システム最適制御手法の開発 （第１報）制御システムと実証試験の概要について

低コスト版個別分散型空調システム最適制御手法の開発 （第１報）制御システムと実証試験の概要について

A Perforated Enhanced Fin to Improve Heat Transfer Performance of a Heat Pump Type Air Conditioner

A Perforated Enhanced Fin to Improve Heat Transfer Performance of a Heat Pump Type Air Conditioner

The Role of Power Consumption and Type of Air Conditioner in Direct and Indirect Water Consumption

The Role of Power Consumption and Type of Air Conditioner in Direct and Indirect Water Consumption

Design framework for variable refrigerant flow systems with enhancement of interoperability between BIM and energy simulation

Heating and cooling energy consumption of buildings accounts for a large portion of global energy use and is significantly affected by the air conditioning system in the buildings. In order to predict the energy performance of buildings, various energy simulation engines have been developed and recently applied to the BIM data of buildings. However, due to the interoperability between them, estimating heating and cooling energy at the design stage of the air conditioning system, in collaboration with the building model, still lacks of efficiency and accuracy. In this paper a highly efficient design framework with enhancement of interoperability that enables the designing of a variable refrigerant flow (VRF) type air conditioning system in BIM environments and to analyze its energy behavior is proposed. The framework covers i) computing the energy load of a building, ii) designing a VRF system that includes equipment selection, layout and piping, and iii) predicting energy consumption by the system with consideration of the building’s thermal properties and annual weather conditions. The novelty of the proposed approach lies in the fact that the layout and piping for air conditioning system are enabled inside a BIM environment to maximize interoperability. We implemented the framework as an add-in program to the commercial BIM software and present its accuracy in comparison with the reference data provided by ASHARE.

RANCANG BANGUN MESIN MINI PENGKONDISIAN UDARA TIPE WATER COOLED CONDENSOR DENGAN PENGONTROLAN TEMPERATUR KABIN BERBASIS MIKROKONTROLER ARDUINO

Abstrak
 
 Penelitian ini berupa rancang bangun sebuah prototipe mini pengkondisian udara tipe water cooled water serta melalukan pengujian prototipe dengan menggunakan variable berupa temperatur nyaman kabin yang dicapai 22,8oC~26,7oC. Dalam pengujian prototype bertujuan mengkaji kinerja hasil rancang bangun berbasis mikrokontroler Arduino Uno untuk pengontrolan temperatur kabin yaitu sensor temperatur DS18B20 dan tanpa menggunakan Arduino Uno. Penelitian ini dilakukan selama satu jam dengan lima waktu pengujian yaitu pada menit 0 ke 10, menit 11 ke 20, menit 21 ke 30, menit 31 ke 40, menit 41 ke 50 dan menit 51 ke 60. Hasil penelitian menunjukan pengunaan mikrokontroler Arduino menghasilkan konsumsi rata-rata daya kompresor berkisar 247watt~264watt dan ketika temperatur minimum evaporator sebesar 8oC tercapai, maka konsumsi daya kompresor mengalami penurunan antara 70,22% sampai dengan 93,29%. Hal yang sama juga terjadi ketika temperatur maksimum evaporator tercapai (20oC), konsumsi daya kompresor juga mengalami penurunan diantara 59,77% hingga 72,02%. Sedangkan hasil pengujian tanpa menggunakan mikrokontroler Arduino konsumsi daya kompresor selalu cenderung konstan pada menit 10 hingga menit ke 60, dimana rata-rata konsumsi daya kompresor berurutan berkisar 267watt~ 275watt untuk tiap capaian temperatur evaporator. Dalam hasil pengujian berbasis mikrokontroler Arduino memberikan penghematan konsumsi energi listrik berupa daya kompresor sebesar 14,65 watt untuk tiap 10 menit pengujian. Hasil penelitian juga diketahui pengontrolan temperatur berbasis mikrokontroler perlu dilakukan agar koefisieb kinerja (coefficient of performance) mesin dapat dijaga konstan serta salah satu langkah agar kompresor tidak bekerja secara terus-menerus (continuously) pada saat temperatur kabin tercapai, dalam hal ini dapat menjaga umur pemakaian kompresor.

集中管理によるビル用マルチパッケージ型空調システムの室内温熱環境および性能評価 （第1 報）計測概要とデータ

集中管理によるビル用マルチパッケージ型空調システムの室内温熱環境および性能評価 （第1 報）計測概要とデータ

Experimental Study for the Effect of Pre-Cooling the Condenser Inlet Air of Split Type Air Conditioning Unit

The reduction of electric power consumption is considered to be a critical issue especially in the areas with elevated temperatures such as Iraq. In Basra city, the electric power consumption due to the air conditioning units (ACU) is so high. In this work, an evaporative cooling unit (ECU) is fabricated and tested where it is retrofitted with the condenser part of a split-type air conditioner. The experimental procedure was done in Basra engineering technical college located in west of Basra city. The present work is categorized in two cases. In case one, the system runs without using the ECU, while in case two the system is tested with ECU. The obtained results show that decreasing the inlet air temperature to the condenser will drop off the condensation and evaporation temperatures. Besides, it decreases the compression pressure ratio and increases the refrigerant mass flow rate. With this modification, it is found that the consumption power is decreased by 26% and COP increased by 90% compared with case one. The second law analysis of the modified system shows that using ECU will decrease most the exergy destruction and losses in the components. Only exergy destruction in the evaporator is increased. The system second law efficiency is improved by 69.5%.

EXPERIMENTAL AND NUMERICAL INVESTIGATION OF METASTABLE FLOW OF REFRIGERANT R-22 THROUGH CAPILLARY TUBE

This study presents an experimental investigation of metastable region take place forrefrigerant flow through adiabatic and non-adiabatic capillary tube of window type airconditioner. Large numbers of experiments are carried out to explain the effect of length ofstraight and helical capillary tube on metastable region under adiabatic and non-adiabaticconditions. for the case of adiabatic capillary tube, three different length are selected(70,100 and 150) cm and two helical capillary tube, the length of each tube is 100 cm withtwo coil diameters (2 and 6) cm. For the non-adiabatic capillary tube, the straight capillarytube suction line is 150 cm while the length of non-adiabatic helical capillary tube is 200 cmwith 8 cm coil diameter. The results show that the length is the most influence parameterson beginning of metastable region. In addition the helical coil tube effect on the beginningof metastable region. As well as for the adiabatic and non-adiabatic capillary tube it isconcluded that mass flow rate is the main parameters on beginning of metastable region.Also effect of length and coiling on both pressure drop and mass flow rate are discussed.The CFD commercial code, ANSYS CFX 16.1 based on finite volume method using Kturbulencemodel considering the homogeneous flow between phases applied to straightcapillary tube. The present numerical data has been validated with the present workexperimental data and with other researchers. A good agreement is obtained which can belead to use ANSYS CFX 16.1 in the design and optimization of capillary tube in airconditioner.

Retracted: Setup and operational cost analysis of 1 Horse power rated split unit inverter and non inverter air conditioner for home usage in Malaysia

Inverter type air conditioner that has been introduced in Malaysian market in recent years, giving an option between the new technology and previous technology which is non-inverter type air conditioner. However, unit price different between them sometime become an obstacle in order to opted for the latest technology. In this article, setup and operational cost analysis has been done with 10 models of 1 horse power rated air conditioners, 7 of them are inverter type air conditioner while only 3 of them are non-inverter type air conditioner. Comparison between inverter and non-inverter type air conditioner has been done with 3 brands of air conditioner. Break-even points for all three brands are less than 1.5 years. In addition, comparison between 7 models of inverter type and 3 model of non-inverter type air conditioner to find out which model is more economical in their segment has been done.

Contribution of Indoor- and Outdoor-Generated Fine and Coarse Particles to Indoor Air in Taiwanese Hospitals

This study quantified the contributions of both indoor- and outdoor-generated particles to the air inside hospitals and examined whether air conditioning type, working area, working hours, and ambient pollution affect these contributions. Indoor and outdoor fine and coarse particles were measured at 33 hospitals, and the building characteristics were recorded. The infiltration factor (Finf) was calculated, and the contributions of both indoor and outdoor particles to indoor air were assessed. Additionally, their influencing factors on the indoor air were evaluated. The Finf values of fine and coarse particles were higher in hospitals with window and signal split type air conditioning than in hospitals with other types of air conditioning. No significant differences in the Finf values between working areas were observed. Outdoor-generated fine and coarse particles were major contributors to the indoor air, regardless of air conditioning type and working area. Higher contributions from indoor-generated fine and coarse particles to the indoor air were recorded in clinic waiting areas and lobbies during working hours than nonworking hours. Ambient air pollutant emissions and air conditioning characteristics influenced the contributions of indoor- and outdoor-generated particles to indoor air according to a regression model. In summary, the contribution of outdoor-generated particles to indoor air must be reduced to improve occupants’ health in hospitals.

The Effect of Refrigerant Charge on the Performance of a Split-Unit Type Air Conditioner Using R22 Refrigerant

Numerous air conditioners are running without a proper refrigerant charge due to leakage and improper charging during installation. Therefore, there is a need to understand the performance of the air conditioner if it is not properly charged for the means of optimal operation and cost saving. This study is focusing on the usage of a used small capacity split-unit type air conditioner using R-22 refrigerant. The objective is to study the condenser performance over a variation of refrigerant charges. From the results, it is clear that the optimum refrigerant charge is 100%. The highest cooling capacity and COP were 3,330 J/s and 3.05 respectively.