Recently Updated
Heating Houses with Solar Power Last Updated on 2010-12-16 00:00:00 Heating the interior spaces of buildings and producing hot water account for a major portion of the energy use in a typical home. Traditional methods for solar space heating maximize interception of sunlight in winter, yet minimize it in summer by placing awnings over windows or landscaping with deciduous trees. Also, sophisticated, low-temperature solar thermal systems are available to collect sunlight for space and water heating. For example, glass-enclosed flat-plate solar collectors on rooftops have black plates that absorb sunlight and transfer the thermal energy to fluids (water or a less-corrosive liquid) passing through flow tubes lying flat against the surface of the plates.   Glazed flat-plate solar collector for heating buildings. A black absorber plate, oriented toward the sun, warms the fluid passing through the flow... More »
Emissions from Buildings Last Updated on 2010-11-12 00:00:00 Buildings, if one includes the greenhouse gases produced from off-site generation of electricity and heat, are the source of nearly one-quarter of the worldwide total from human activities. [1] Heating and cooling, water heating, and lighting consume most of the energy in commercial and residential buildings. Space Heating and Cooling Key to energy conservation in buildings is minimizing unwanted exchanges of thermal energy between the interior and the environment, either by conduction, by convection , or by radiation. The extent of these energy transfers depends on air and moisture leaks, insulation levels, thermal properties of windows and doors, and HVAC (heating, ventilating, and air conditioning) equipment. Thermal Leakage The outer shell of a building serves as a barrier to impede thermal exchange between the building and its surroundings. Air leaks driven by... More »