[...]... insulated buildings and buildings with high air change rates the type of space heating assumes importance in the determination of plant energy output Qp INTERMITTENT HEATING The foregoing Examples 1.4 and 1.5 are based on the assumption that the heating plant operates continuously throughout the heating season This is the case for factories working a system of three shifts, hospitals, airport terminals,... of linear thermal expansion (m/mK) density (kg/m3) sum of Heat flow into or out of a building is primarily dependent upon the prevailing indoor and outdoor temperatures If both are at the same value heat flow is zero, and the indoor and outdoor climates are in balance with no heating required During the heating season (autumn, winter and spring), when outdoor temperature can be low, the space heating. .. vapour from the lungs, and sweating In the winter, therefore, latent heat gain indoors is inevitable during occupancy periods Cooking, dishwashing and laundering add to the latent heat gains If the building is heated, the air is usually able to absorb the vapour production, with a consequent rise in vapour pressure In an unheated and occupied building condensation may occur on the inside surface of the... multistorey building showing prevailing wind pattern rates, and include stack effect in the building resulting from stairwells, lift shafts, unsealed service shafts and atria, and how well the building is sealed Thus from Q=M.C.dt, Qv=(V.ρ.N.C.dt) 3600, and if standard values of air density and specific heat capacity are taken, Qv=0.33 NV dt (1.3) BUILDING SHAPE AND ORIENTATION This affects the way indoor temperature... or damping effect upon the rise and fall in temperature of the building structure for an intermittently operated plant They in effect act as a heat store ENVIRONMENTAL CONTROL BY STRUCTURE The building services industry is increasingly exposed as having a major role to play in limiting nitrous oxide and CO2 emissions through correct plant selection and maintenance It can be seen from the foregoing analysis... building envelope to continuous and intermittent space heating Later in this chapter this topic is introduced again 1.3 Plant energy output The determination of building heat loss, which forms the basis for the calculation of plant energy output Qp, is dependent upon the mode of plant operation and hence the mode of occupancy It can be divided into three categories: continuous, intermittent and highly intermittent... energy output introduction of tempered fresh air to maintain indoor air quality unless the building is lofty Temperature ratios F1 and F2 allow the determination of indoor air temperature tai and environmental temperature tei for a given building envelope and space heating system Along with dry resultant temperature tc (the design index) and mean radiant temperature tr, which can also be determined, we... structure and its composition used in a building have a significant effect upon the way in which plant and space heating systems need to operate to maintain indoor design temperature The concept extends further to the levels of CO2 emission generated as a result of the building construction process, including manufacturing of materials and their transport to site The consumption of primary energy in the... exposed to cold infiltrating air at any instant In practice the full infiltration heat loss is employed in plant selection It follows therefore that the rate of infiltration and hence the heat loss due to infiltration of outdoor air are dependent upon air temperature and wind speed Further factors that relate to the building design may also influence infiltration 3 4 Heat requirements in temperate climates... long been known that building envelopes for factories and workshops having traditional transmittance coefficients (average U value approximately 1.5 W/m2 K) and relatively high rates of infiltration (above 1 air change per hour) require higher levels of convective heating than radiant heating to maintain indoor design conditions This is based on the knowledge that, living in the natural world as we . 0171 865 0066 Heating and Water Services Design in Buildings Keith J.Moss I. ENG., ACIBSE Visiting lecturer in Building Services Engineering to The City. of information 247 Index 249 vi Contents Preface Heating and Water Services Design in Buildings has been written following 13 years in the industry and