Methods of reduction of power consumption for cooling residential buildings in the hotand dry climate of northern regions of tajikistan Методы снижения расхода энергии на охлаждение жилых зданий в условиях сухого жаркого климата северных регионов Таджикистана

• Main Author: Usmonov Shukhrat Zaurovich
• Format: Article
• Language: English
• Published: Moscow State University of Civil Engineering (MGSU) 2013-09-01
• Series: Vestnik MGSU
• Subjects: solar glazing; transmittance of solar heat; ventilation rates; comfort; optimum temperature; energy efficiency; energy consumption; Central Asia; Tajikistan; солнцезащитные устройства; коэффициент пропускания солнечного тепла; кратность воздухообмена; комфорт; оптимальная температура; энергоэффективность; расход энергии; Центральная Азия; Таджикистан
• Online Access: http://vestnikmgsu.ru/files/archive/RUS/issuepage/2013/9/10.pdf

Reduction of energy consumption by devices designated for cooling residential buildings in the hot and dry climate of Central Asia is a most important challenge. The author uses a large apartment building (105 series), built in the 1980ies in the city of Khujand, to study the energy consumption required to cool the building after its renovation and modernization. Basic methods of reducing energy consumption for cooling buildings in hot, dry climates were applied. According to the findings of the research performed using a model residential house, ambient solar heat gain is reduced by 65 % during the hot season lasting from April to September. To cool the building, old windows are replaced by new insulated ones having a low solar heat gain coefficient (SHGC — 0.4) and external awnings are installed to protect windows looking to the West.The typical internal room temperature of +25 °C is assumed for the thermal calculations in the summer conditions. In summer, the outside temperature exceeds 40 °C in the northern regions of Tajikistan. A typical difference between the inside and outside air temperature is 15 °C. This extensive temperature difference has a negative effect on the human body. Frequently, the human body has no time to adapt to rapid temperature changes. Aged and sick people are especially sensitive to rapid temperature changes. They are more likely to experience headaches, exacerbated hypertension, atherosclerosis and other diseases. Moderate fluctuations of the air temperature are preferable, as they reduce pressure on the body's thermoregulatory mechanisms.It is noteworthy that people who remain inside buildings are not isolated from the external environment, and they must be careful to avoid sudden temperature changes. In the European regulations aimed at warm, rather than hot summer conditions, internal residential air temperature of +25 °C is considered comfortable. On the contrary, the internal temperature in residential buildings in northern Tajikistan varies from +27 °C to +28 °C. High temperatures can cause significant discomfort in the hot and dry climate like the one in Tajikistan.It is recommended to remain indoors during the day, to keep the windows open at night, and to run air conditioners in residential buildings in summer at certain time intervals.The author proposes a method of optimization of the design temperature of residential rooms using PMV and PPD indices. Optimal air circulation through open windows at night is identified to ensure comfort in modernized residential buildings.<br>Рассмотрены основные методы снижения расхода энергии на охлаждение здания в условиях сухого жаркого климата. Определена оптимальная расчетная температура в жилых помещениях в период охлаждения с учетом индексов PMV и PPD. На основании модельных исследований в модернизируемом жилом доме выявлена оптимальная кратность воздухообмена через окна в ночное время для обеспечения комфорта в помещениях.