scholarly journals On the Energy Efficiency of Indoor Air Conditioning

Author(s):  
S. N. Osipov ◽  
A. V. Zakharenko ◽  
E. M. Shirokova

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.

2011 ◽  
Vol 250-253 ◽  
pp. 3021-3024
Author(s):  
Qing Hai Luo ◽  
Peng Fei Zhang ◽  
Xiu Fei Yang ◽  
Jun Zou

A novel window type air-conditioner with energy recovering was experimented. The experimental prototype can make fresh air exchange heat with exhaust air in an additional heat exchanger, which consist no additional moving parts. The EER (energy efficiency ratio) of the experimental air-conditioner (EAC) is increased by 17.4~37.3% than that of the original ordinary window type air-conditioner (OAC). On the other hand, the fresh air proportion of the EAC is increased by 20% or so than that of the OAC, so indoor air quality can be greatly improved via the EAC; however the indoor noise of the EAC is increased by 3.2 dB or so. The novel experimental prototype is of great significance for energy efficiency.


2020 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Ghodbane Mokhtar

Air conditioning is one of the indispensable conditions of well-being in human life, so the face of this research to provide this basic necessity in remote areas and in desert places far from power grids. To achieve this goal, solar air conditioning has been adopted, where the compressor was replaced by an ejector, a parabolic trough solar collector and a small pump; this means that the solar air conditioner does not need a huge amount of electrical energy to operate. This paper is studding the thermodynamic cycles of this air conditioner as a function of changing the climatic conditions of Bouzaréah region in Algeria under several practical conditions of heat exchangers (Condenser, Evaporator and Generator). This study will allow the determination of the optical and thermal efficiency of the solar collector used as a solar thermal generator, refrigeration subsystem performance (COPEje) and system thermal ratio of the air conditioner, where the cooling load is estimated at 18 kW.


2011 ◽  
Vol 19 (02) ◽  
pp. 131-140
Author(s):  
QUBO LI ◽  
DEMISS A. AMIBE ◽  
NORBERT MÜLLER

An air conditioning system using water as refrigerant (R718) that compresses water vapor with multistage stage variable speed axial compressor with intercooling between stages by water injection is considered. Four stage compression with flash intercooling resulted in 50% improvement of coefficient of performance (COP) at full load compared to conventional refrigerants like R134a. The energy efficiency of an air conditioning unit is specified by seasonal energy efficiency ratio (SEER). SEER is defined as the ratio of cooling output of an air conditioner measured and electrical energy consumption as per AHRI 210/240 during cooling season. The SEER is computed after determining the evaporator cooling capacity and the electrical energy demand of the compressor at each bin temperature using assumed compressor isentropic efficiency, mechanical efficiency and electrical efficiency and multiplying by the weight of each bin temperature to determine the total for the cooling season. As a result of multistage compression, best part load performance of water as a refrigerant and operation of compressor near design point at part load due to variable speed drive, 50%–60% improvement in SEER is obtained compared to the best available in the market using conventional refrigerants such as R134a with single stage compression.


2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.


2019 ◽  
Vol 111 ◽  
pp. 04043
Author(s):  
Louis Cony-Renaud-Salis ◽  
Nouamane Belhaj ◽  
Olivier Ramalho ◽  
Marc Abadie

Home represents an important part of the time spent indoors and is the emblematic place of a family need, e.g. well-being, comfort and safety. In France, health agencies provide information and raise the awareness of the public on health risks and on factors likely to affect the quality of indoor air. However, indoor air quality remains difficult to assess for health investigators. A solution would be to resort to field measurements, but they are expensive and hard to apply to a large-scale population when considering the numerous pollutants found indoors. Therefore, numerical simulation represents a good alternative when accurate and realistic input data are used. We already designed such a model of a dwelling prototype using a type 98 coupling procedure between CONTAM (airflow rates and pollutants concentration determination) and TRNSYS (thermal and moisture calculation). We paid a lot of attention to the details that we thought were important: dwelling multi-zonal representation, envelope airtightness, ventilation system elements (pressure driven inlet and outlet, ducts, fan characteristics), presence of furniture, people activity and location… Nevertheless, the design of this simulation requires a very specific care. This very last point naturally induces a debate: is it necessary to design the simulation to be as accurate and realistic as it actually is, or will a simpler model provide similar results? In this study, we aim to answer that question by evaluating the sensitivity of the ULR-IAQ multipollutant index, defined in a previous study, to different levels of modelling complexity.


Author(s):  
Essam E. Khalil

Energy Efficiency and Indoor Air Quality in the healthcare applications and particularly in surgical operating theatres are important features in modernized designs. The various reasons for deviation from obtaining optimum IAQ and energy efficient buildings are listed. The air conditioning systems serving the operating rooms require careful design to minimize the concentration of airborne organisms. Numerical approach is an appropriate tool to be utilized to adequately identify the airflow patterns temperatures and relative humidity distributions and hence energy efficient designs.


Author(s):  
Demiss A. Amibe ◽  
Qubo Li ◽  
Norbert Mu¨ller

An air conditioning system using water as refrigerant (R718) that compresses water vapor with multistage stage variable speed axial compressor with intercooling between stages by water injection is considered. Four stage compression with flash intercooling resulted in 50% improvement of coefficient of performance (COP) at full load compared to conventional refrigerants like R134a. The energy-efficiency of an air conditioning unit is specified by seasonal energy efficiency ratio (SEER). SEER is defined as the ratio of cooling output of an air conditioner measured and electrical energy consumption as per AHRI 210/240 during cooling season. The SEER is computed after determining the evaporator cooling capacity and the electrical energy demand of the compressor at each bin temperature using assumed compressor isentropic efficiency, mechanical efficiency and electrical efficiency and multiplying by the weight of each bin temperature to determine the total for the cooling season. As a result of multistage compression, best part load performance of water as a refrigerant and operation of compressor near design point at part load due to variable speed drive, 50–60% improvement in SEER is obtained compared to the best available in the market using conventional refrigerants such as R134a with single stage compression.


2008 ◽  
Vol 60 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Milica Ljaljevic-Grbic ◽  
Jelena Vukojevic ◽  
M. Stupar

Fungi have been implicated as quantitatively the most important bioaerosol component of indoor air associated with contaminated air-conditioning systems. rarely, indoor fungi may cause human infections, but more commonly allergenic responses ranging from pneumonitis to asthma-like symptoms. From all air conditioner filters analyzed, 16 fungal taxa were isolated and identified. Aspergillus fumigatus causes more lethal infections worldwide than any other mold. Air-conditioning filters that adsorb moisture and volatile organics appear to provide suitable substrates for fungal colonization. It is important to stress that fungal colonization of air-conditioning systems should not be ignored, especially in hospital environments.


Sign in / Sign up

Export Citation Format

Share Document