Basic design steps for air-conditioning system design and its main design procedures-part 1

Step 1: Familiarise yourself with the original design information of the building you are designing

Including: relevant documents provided by Party A about the project, the use of the building and its process requirements, the design assignment, and the building operation drawings.

Step 2: Information Research

This includes: reviewing relevant design information (manuals, codes, standards, measures, etc.) and collecting products of relevant equipment and materials.

Step 3: Determine meteorological parameters for indoor and outdoor design

According to the design of the building is located in the region, check the outdoor air winter and summer meteorological design parameters; according to the design of the building's use of the function, to determine the indoor air winter and summer design parameters.

Step 4: Determine building thermal and other parameters of the designed building

According to the composition of the building's external envelope, calculate the heat transfer coefficients of external walls, roofs, external doors, external windows and other parameters; according to the composition of the building's internal and external envelopes, calculate the heat transfer coefficients of internal walls, floor slabs, external doors, external windows and other parameters; according to the building's use function, determine the number of people in the room, lighting load, equipment load, working time period and other parameters.

Step 5: Calculation of air-conditioning heat and humidity loads

Calculate the air-conditioning heat and humidity loads (residual heat and humidity) of the designed building under the most unfavourable conditions; compare the energy-saving solutions for the building and determine the reasonable air-conditioning heat and humidity loads. Step 6: Determine the best air-conditioning programme Through technical and economic comparisons, select and determine the air-conditioning system mode, cooling and heating source mode, and air-conditioning system control mode suitable for the designed building.

Step 6: Calculation of air volume and airflow organisation

According to the calculated heat and humidity load of air-conditioning and the temperature difference of air supply, determine the state of air supply in winter and summer and the air supply volume; according to the requirements of the working environment of the designed building, calculate and determine the minimum fresh air volume; according to the air-conditioning mode and the calculated air supply and return volume, determine the form of air supply and return outlets, arrange the air supply and return outlets, and carry out the design of airflow organisation.

Step 7: Air-conditioning water and air system design

Lay out air conditioning air ducts, carry out hydraulic calculation of air duct system, determine pipe diameter, resistance, etc.; Lay out air conditioning water ducts, carry out hydraulic calculation of water piping system, determine pipe diameter, resistance, etc.

Step 8: Design and selection of major air-conditioning equipment

According to the air treatment programme of the air-conditioning system and combined with the i-d diagram, the design and calculation of air-conditioning equipment selection is carried out; the capacity (heat load) and air supply volume of the air treatment equipment are determined, and the structural form of the surface heat exchanger and its thermal parameters are determined; according to the hydraulic calculation of the ductwork system, the flow rate, air pressure and type of the fan are determined.

Step 9: Design of smoke protection and exhaust systems

Step 10: Cold and heat source plant room design

According to the capacity of the air handling equipment, determine the capacity and model of the cold source (chiller) or heat source (boiler); according to the hydraulic calculation of the piping system, determine the flow rate, head and model of the pump.

By Sammi