【HVAC Version】Daily Question 20180408

Heat gain refers to the heat that enters a room at a given moment and the heat generated within the room; this heat can be in the form of sensible heat or latent heat, or a combination of both. The cooling load refers to the amount of heat that air-conditioning systems must remove from a room per unit of time in order to maintain a constant room temperature; in other words, it is the total amount of heat supplied to the indoor air per unit of time. Under conditions of intermittent operation of the air conditioning system, the room temperature fluctuates to a certain extent, causing heat storage and release in the objects inside the room (including the building envelope). As a result, the air conditioning unit has to remove more heat from the room in order to maintain the desired temperature and humidity. The amount of heat removed by the air conditioning unit under such unstable operating conditions to maintain indoor conditions is referred to as the \"heat removal rate\"; in engineering terms, this is often called the startup load, and it represents the actual cooling capacity of the air conditioning unit. The heat gain does not necessarily equal the cooling load. Because only the convective component of the heat gain can be immediately absorbed by the indoor air. The radiant component of heat gains is absorbed and stored by the surfaces of objects inside the room through the air; the temperature of these surfaces rises. Once their surface temperature exceeds that of the indoor air, these objects release the stored heat into the air via convection, and it is at this point that the released heat becomes a cooling load. This conversion process involves attenuation and delay, resulting in the peak value of the cooling load being lower than that of the heat gain, and the peak value of the cooling load occurring at a later time than that of the heat gain.

Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are only equal when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity.

Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are only equal when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity

Heat gain refers to the heat that enters a room at a given moment or is generated within the room; this heat may consist of sensible heat or latent heat, or both. Heat gain through the thermal transfer of the enclosure, as well as heat dissipation from lighting fixtures and equipment, all falls under sensible heat gain. The heat dissipation of people or water-containing equipment indoors involves both sensible heat gain and latent heat gain (the heat carried into the air by the evaporation of water vapor). The cooling load refers to the total amount of heat absorbed by the indoor air per unit of time, under the condition of maintaining a constant room temperature; in other words, it is the amount of heat removed from the indoor air per unit of time by air-conditioning systems that use ventilation (or other cooling methods). The heat gain does not necessarily equal the cooling load. This is because only the convective component of the heat gain can be immediately absorbed by the indoor air, whereas the radiative component of heat gain cannot be directly absorbed by the air. The radiant heat (long-wave or short-wave) that enters a room is absorbed and stored by various objects within the room through the air; the temperature of these objects rises. Once their surface temperature exceeds that of the air in the room, they release the stored heat into the air via convection, and it is this convectively released heat that constitutes the cooling load.

Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are only equal when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity

Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are equal only when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity.

Heat gain refers to the heat that enters a room at a given moment or is generated within the room; this heat may consist of sensible heat or latent heat, or both. Heat gain through the thermal transfer of the enclosure, as well as heat dissipation from lighting fixtures and equipment, all falls under sensible heat gain. The heat dissipation of people or water-containing equipment indoors involves both sensible heat gain and latent heat gain (the heat carried into the air by the evaporation of water vapor). The cooling load refers to the total amount of heat absorbed by the indoor air per unit of time, under the condition of maintaining a constant room temperature; in other words, it is the amount of heat removed from the indoor air per unit of time by air-conditioning systems that use ventilation (or other cooling methods). The heat gain does not necessarily equal the cooling load. This is because only the convective component of the heat gain can be immediately absorbed by the indoor air, whereas the radiative component of heat gain cannot be directly absorbed by the air. The radiant heat (long-wave or short-wave) that enters a room is absorbed and stored by various objects within the room through the air; the temperature of these objects rises. Once their surface temperature exceeds that of the air in the room, they release the stored heat into the air via convection, and it is this convectively released heat that constitutes the cooling load.

Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are only equal when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity

Briefly explain the concepts of heat gain in air-conditioned rooms during summer and the indoor cooling load, as well as the relationship between the two. Answer: Heat gain: The total amount of heat entering the room from indoor and outdoor heat sources ； Cooling load: The amount of heat that must be removed from a room in order to maintain the indoor temperature and humidity at specified levels. The cooling load and the heating load are sometimes equal and sometimes not; they are only equal when there is no heating by radiation, or when the structural elements and indoor objects do not possess any heat storage capacity