Weak current College】 【how to calculate the temperature and humidity machine room within the required cooling capacity.

<br> <br> In order to determine the air conditioner's capacity to meet the room temperature, humidity, cleanliness and air speed requirements (hereinafter referred to as 4 degrees). You must first heat load of the computer room. <br> Room .of mainly from two aspects: <br> The first is the internal heat generated in the engine room, it includes: indoor computer and external equipment for heat, the engine room facilities and room equipment of heating value (electric heating, steam, water and .other heating element). The calorific value of sensible heat, latent heat; <br> Lighting fever (sensible heat); <br> Staff of fever (sensible heat small, large latent heat); <br> As a result of evaporation, .condensation heat generated (latent heat). <br> The second is the engine room external heat generated, it includes: <br> Conduction heat. Through building ontologies into heat, such as walls, roofs, dividers and ground heat incoming room (sensible .heat); <br> Radiation heat (also known as radiant heat). Because the sun radiation from Windows directly into the room heat (sensible heat); <br> Convection heat generated. From the Windows and doors, gaps in the heat of .trespass outdoor air (also contains water vapour) the heat generated (sensible heat, latent heat); <br> In order to make indoor staff reduction fatigue and conducive to human health and the introduction of fresh air to the heat (including the sensible heat .and latent heat). <br> In short, the human body gives off heat, thermal gap wind penetrated and ventilation into heat, not only to keep the room temperature rises, so does the Interior moisture content, and therefore requires dehumidification. This part .is called latent heat load, thermal load, and the engine all devices distributed heat only the indoor temperature to rise, the heat load is known as the sensible heat load. And General Hotel, offices, conference rooms, and so represent a large proportion of .latent heat is, computer-controlled machine room, heat load is a sensible heat load. Therefore, for the heat load of different occasions should use different types of air conditioners. Usually sensible heat ratio (SFH) as an important indicator of the air conditioner .. <br> General computing (also known as estimate) <br> In the initial design phase, the computer lab in order to accelerate the capacity of selected air conditioners may use this method, the unit area required cooling capacity to estimate. <br .> Computer room (including PBX room): <br> The floor is high, 250 ~ 300kcal/m2h <br> The lower floor, 150 ~ 250kcal/m2h (according to equipment suitable for density and decrease) <br> Office (wired .): 90kcal/m2h <br> Easy heat load calculation <br> Computer room air conditioning load, mainly from computer equipment, peripherals and engine room equipment of heating value, approximately 80% of total calories, followed by heat conduction of heat, lighting ., radiant heat, etc., the calculation method and a general load calculation the same air conditioned room. The manufacturer of your computer, generally provide device specific calorific value. Electricity consumption under computer calculation of its calorific value. <br> A. calculation .of calorific value of the external device <br> Q = 860N ¢ (kcal / h) <br> Type: N: electricity consumption (kW); DIA: while using the coefficient (0.2 ~ 0.5); 860: power of thermal equivalent ., ie all the lkW power into heat energy generated by heat. <br> B. calculation of calorific value of Q = host 860 × P × h1 × h2 × h3 <br> In the formula, P: total output (kW); .<br> H1: while using the coefficient; <br> H2: utilization coefficient; <br> H3: load work uniform coefficient. <br> The engine room the power of various devices, to the engine room the device's maximum power consumption, .but the power consumption is not wholly converted to heat, so you must use the above three factors to amend, these coefficients and with computer system structure, function, use, work status and electronic components. Take the total factor of General 0.6 ~ 0.8 as .well <br> C. calculation of lighting equipment <br> Room lighting electricity consumption, some becomes light, some becomes hot. Become part of the light due to buildings and equipment, the absorption and become hot. Lighting equipment of thermal load is calculated .as follows: <br> Q = C × Pkcal / h <br> In the formula, P: lighting devices of nominal rated output power (W); <br> C: each output lW calories (kcal / hW), typically from .blazing lights 0.86, fluorescent 1.0. <br> D. human body heat <br> Human body heat is placed through the skin and the respiratory organ, this thermal result contains water vapour, its heat load should be sensible heat and latent heat load. .<br> Human body heat with work issued by the State. Room staff can handle light physical work. When the room temperature is 24 ° c, the sensible heat load is the latent heat load is 56cal 46cal; when the room temperature is 21 ° .c, the sensible heat load is the latent heat load is 65cal 37ca1. In both cases, the total heat load are 102cal. <br> E. envelope of conductive heat <br> Through room roof, walls, dividers, envelope into the engine .room of the conduction of heat is a season, time, geographical location and the Sun's radiation angle and other related content. Therefore, in order to accurately find this volume is a very complex issue. <br> When the indoor and outdoor air temperature remains .a stable state, by plane shapes wall heat incoming room can anxiashijisuan: <br> Q = KF (t1-t2) kcal / h <br> Type, K: building envelope of thermal conductivity (kcal/m2h ° c); <br .> F: enclosure size (m2); <br> T1: room temperature (° c); <br> T2: calculation of outside the room temperature (° c). <br> When the calculation is not in direct contact with outdoor .air in the envelope as dividers, etc, indoor and outdoor temperature difference calculation should be multiplied by the correction factor, its value is typically take 0.4 ~ 0.7. Thermal conductivity materials used are shown in the following table: <br> Materials for thermal conductivity .(kcal/m2h £) material thermal conductivity (kcal/m2h £) <br> Ordinary concrete 1.4 ~ 1.5 gypsum board 0.2 <br> Lightweight concrete 0.5 ~ 0.7 asbestos cement Panel 1 <br> Mortar 1.3 soft fibreboard 0.15 <br> Plaster .0.5 fiberglass 0.03 <br> Brick 1.1 galvanized steel 38 <br> Glass 0.7 aluminum plate 180 <br> Wood 0.1 ~ 0.25 <br> F. from glass penetration of solar radiation <br> When the glass is affected by sunlight, part reflection ., absorption, part is glass left through the glass into the engine room converted into heat. The heat absorbed by the glass to the glass temperature rise, part of which by convection heat into the room has also become a load. <br> Through the .glass into the indoor thermal calculation according to the following type: <br> Q = KFq (kcal / h) <br> Type, K: solar radiation heat penetration coefficient; <br> F: window area (m2); <br> .Q: through the Windows into solar radiation heat intensity (kcal/m2h). <br> Penetration coefficient K value depends on the type of the window, usually take 0.36 ~ 0.4. <br> Q solar radiation intensity with latitude, season, and .time, and the angle with the sun exposure. Specific values refer to the local weather information. <br> G. ventilation and heat load of outdoor intrusion <br> In order to give the computer room staff continually added fresh air, as well as .ventilation to maintain the positive pressure in the engine room, the need to adopt a new outlet of air conditioning equipment to computer room into outdoor fresh air, the fresh air will become the heat load. The gap through the doors, Windows and switch and intrusion .of outside air quantity, degree of Random House's seal, the number of access and outdoor wind speed changes. This kind of heat load is usually very small, if needed, it can be removed for the room rate to determine the heat load. <br .> H. other thermal load <br> In the room, in addition to the thermal load, use the work as is, electric iron, vacuum cleaner, etc. will be the heat load. Since these devices of power consumption generally smaller, can .roughly according to its rated input power and reactive power of the product of thermal equivalent. In addition, the engine uses lots of transmission cable and body heat. It is calculated as follows: <br> Q = 860Pl (kcal / h) <br .> Type, 860: power of thermal equivalent (kca1 / h); <br> P: per metre cable power consumption (W); l: cable length (m). <br> In short, the engine room heat load from the .ah the heat load to determine. <br> <br> <br>.