Harmonic reaction method: in load calculation, the key to forming cooling load is to obtain the proportion of radiation part in the cooling load, because the convection part directly becomes the cooling load, and the process of transforming radiation heat into cooling load in harmonic reaction is shown in the following figure:
The radiation disturbance heat is cast on the plate wall, which is equivalent to increasing the temperature of the air boundary layer on the surface of the plate wall. After the wall absorbs heat, the temperature will release heat to the room in the form of convection, and the released heat is the cooling load.
Cooling load coefficient method: The cooling load coefficient method is a simplified calculation method based on Z transfer function. This method combines heat gain calculation and load calculation into one, and directly obtains the hourly cooling load of various disturbance sources through the cooling load coefficient.
1, cooling load coefficient method to determine the cooling load of air-conditioned rooms.
(1) Maintain the cooling load caused by the transient heat transfer of the structure; Cold load caused by transient heat transfer of external wall and roof; Cooling load caused by heat transfer of indoor maintenance structures (such as interior walls and floors).
(2) The cooling load caused by solar radiation entering the room through the glass.
(3) The cooling load caused by heat dissipation of indoor heat source.
Cooling load caused by lighting heat dissipation; Cold load caused by human body heat dissipation; ? Cold load caused by heat dissipation of equipment and appliances; The summer cooling load of air-conditioned rooms should be determined according to the comprehensive maximum cooling load of each hour. If the fresh air of the air-conditioning system is sent directly to the room for treatment (when the fresh air does not bear the indoor air load), the cooling load of the air-conditioned room should also include the fresh air load.
Extended data:
Cooling load refers to the heat that the air conditioning system must take away from the room at a certain moment in order to maintain the indoor set temperature, or the cold energy that needs to be supplied to the room at a certain moment. Room heat refers to all kinds of heat that enters the room through the maintenance structure and radiates inside the room.
It consists of two parts: first, the heat entering the room due to solar radiation and the heat transferred to the room by the temperature difference between indoor and outdoor air through the maintenance structure; The other part is the heat emitted to the room by human body, lighting, various process equipment and electrical equipment. According to different properties, the room heat can be divided into latent heat and sensible heat, and sensible heat includes convection heat and radiation heat.
Air conditioning system relies on air supply to take away indoor heat, which can only be convection heat. This is the load. However, the above heat contains radiation components that cannot be absorbed by air supply. This part of radiation can be converted into convection component through the heat storage and heat release effect of radiation envelope.
This change will inevitably lead to peak shaving and delay, and the result is that the heat gain curve becomes flat when it becomes a load curve. The peak load is less than the peak heat. In other words, heat gain and load are two different concepts, and heat gain contains radiation components.