Family central air conditioning system design content mainly includes: load calculation, system design, selection and pipeline layout.

1, air conditioning load calculation

Air conditioning load calculation for reasonable selecting air terminal processing equipment and determine the cold, heat source equipment capacity provides the basis. Air conditioning load calculation including summer cold load calculation and winter heat load calculation. In the schematic design stage, can use load estimate index in load calculation. In the design of construction stage, according to standard requirement, deal with the air conditioning room on the basis of load calculation item by item.

Sure air conditioning load, for residential to palisade structure load primarily room, should consider the intermittent load additional coefficient 1.10-1.20. At the same time, still should consider adjacent room without when the air conditioning temperature difference caused by the heat load.

Determine the total load of air conditioning system, should give full consideration to the particularity of the residential use. Residential mainly by the bedroom, sitting room, dining-room, kitchen and toilet composition, kitchen and toilet generally do not set air conditioning, and the bedroom, sitting room, dining-room also open an account the probability of air conditioning is very small. So at the same time use coefficient is low, generally can be according to 0.5 ~ 0.7 selection.

Load calculation should also consider the new-wind load, no fresh air into the air conditioning system is not complete household central air conditioning system.

2, system design and choice

Choose air conditioning system, should fully consider using occasions, use characteristics and the requirement of owner, and other factors.

(1) duct type air conditioning system duct type air conditioning system load regulation ability is bad, the unit is according to return air parameters of compressor control the stop. The general can't send air volume air conditioning load with the room changes, when a room needs air supply, other don't need air conditioning room also has the wind into. Integral unit should try to close to the service area arrangement, in order to make back to duct short straight as far as possible. Because of the air treatment equipment in integral unit inside, fresh air into very convenient. For the lower layer air conditioning area, such as housing, the main duct arrangement as far as possible in the hallway, sitting room periphery, in order to adornment processing, pipe all should set airflow regulating valves. Air ports to send double side draught shutter mainly, but also need according to decorate, the top sent the article or scattered flow draught seam type tuyere, etc.

(2) air source water chiller/heater air source water chiller/heater compressor is divided into fixed speed and variable speed two kinds. For fixed speed water chiller/heater, indoor load change easy to cause the compressor frequent up, stop, because water system in small scale, consideration should be given to the thermal stability of the system requirements, lest cause in partial load compressor frequent starting. So the system should be set up in storage tank, or increase supply and return water temperature difference value.

For winter intermittent operation, and the temperature outside is lower and the system is easy to icy area, can will evaporator and circulating water pump and outdoor and indoor auxiliary engine of host separate. Indoor and outdoor auxiliary machine with host refrigerant tube connection. In cold areas, winter outdoor temperature is lower, according to the cooling load of the summer choose water chiller/heater, heat in winter is often can't meet the requirements of the winter heat load, at this time, should consider to choose auxiliary electrical heating to increase heat quantity.

Water control generally have three ways: a variable flow is way, way flow by interior thermostat control unit out of the electric two valve open or closed, when fan coil to stop operation, the valve is closed. Air conditioning water on the manager the by-pass installed differential pressure, to stabilize the flow into the unit. 2 it is constant flow ways, the constant flow way by interior thermostat control unit out of the electric three-way valve open or close; Three is in constant flow and variable flow of mixed between way, the way of the host nearly part of the unit using electric two valve, and other units used the three-way valve, at this point, saves the pressure difference bypass valve, which used the way should pay attention to the second valve and the number of the 3-way valve (pos with. Three-way valve small number, can lead to host for the flow of water is too low and stop.

(3) VRV variable refrigerant flow heat pump units VRV system design should be considered when the influence of refrigerant leakage. VRV system in a long pipe refrigerants, refrigeration dose is more, construction undeserved will leak.

When the calculation results more than dangerous concentrations, can adopt the following two measures: 1) the room to offer interconnected ventilation window, ventilated area should be greater than or equal to 15% of the area of the floor; 2) R22 leakage alarm device and set the interlocks control and exhaust fan.

3, piping design

Piping design including water pipe system design and duct system design. Water pipe system, for mains, tube the water velocity is less than 1.2 m/s, for pipe, tube the water velocity appropriate as 0.6 m/s or so. Deal with conduit road for friction calculation, checking the host for water pump head whether meet the requirements, to avoid air is trapped in the tube, pipes of the top automatic vent valve should be installed. For condensate system, horizontal line along the flow direction should be generally keep not less than 5 ‰ slope, condensed water tube can be used or RPVC galvanized steel tube, condensed water tube can be used galvanization steel tube or UPVC pipes, condensed water tube can be used for 10 mm thickness of retardant type bubble xiangsu materials for thermal insulation.

In order to reduce the air flow noise, duct in wind speed should be less than 6 competent m/s, pipe should be less than 4 wind speed m/s, send, return air mouth YiQu wind speed of 2 m/s.

 

 

 

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