Main factors

The thermal comfort of the human body depends on the indoor environment, I .e. the indoor temperature, the relative humidity and the airflow speed.

Thermal comfort

best range

• Winter temperature 18~25 degrees Celsius, relative humidity 30% ~ 80%;
• Summer temperature 23~28 degrees Celsius, relative humidity 30% ~ 60%;
• The indoor air flow velocity is 0.1~0.7 m/s.

temperature and humidity monitoring system

Thermal balance of the human body

The main ways of heat dissipation from the human body are: conduction, radiation, convection and evaporation. The human body is constant temperature. If the heat released by the human body is greater than the heat generated by its metabolism, the human body will feel cold; on the contrary, if the heat released by the human body to the environment is less than the heat generated by the metabolism, the heat will accumulate in the human body, and the human body will feel the heat.

Appropriate architectural comfort

• Can provide a good place to work and live
• Avoid the occurrence and transmission of various diseases
• The rest of the human body, maintenance has important benefits
• It plays an important role in improving people's health.

Factors affecting the thermal comfort of the human body

Subjective factors:

• Metabolic rate; people with high metabolic rate are not afraid of cold, but afraid of heat; people with low metabolic rate are not afraid of heat, but afraid of cold
• Clothing situation: different types of buildings, different functional rooms, people's clothing situation is not the same

Objective factors:

• Air temperature: the most important factor, which directly determines whether the human body feels cold or hot. The most suitable indoor temperature for the human body is 24~28 degrees Celsius
• Air relative humidity: high relative humidity makes people feel stuffy and sticky; low relative humidity makes people uncomfortable to breathe, and a large amount of floating dust in the air further pollutes the indoor air. The relative humidity of indoor air in winter should be 40% ~ 80%
• Air flow speed: indirectly affects the thermal comfort of the human body. The air flow can take away the exhaust gas emitted by the human body, which can reduce the carbon dioxide concentration around the human body. The appropriate speed can increase the evaporation of the human body surface and give people a fresh feeling. The best air flow speed in winter is 0.2~0.5 m/s.

Thermal Comfort Goals

• Basic goal: Comfort
• Ideal Standard: Health
• Development trend: high efficiency and energy saving

Thermal comfort during heating period in China

Excessive or insufficient heating:Different from the solar radiation, the room on the south side is overheated, causing people to open windows to cool down, losing heat, and outdoor dust also pollutes the indoor air. The temperature in the room on the north side is low and it feels uncomfortable.

Poor air mobility and serious pollution:Old buildings are not very concerned about building ventilation, indoor oxygen content will be low, high concentration of dioxide, great harm to human body.

Winter indoor dry, low relative humidity:In the northern region, there is less precipitation, high indoor temperature, large air evaporation, more pollutants, and more water loss from the human body, which will feel dry and uncomfortable.

Means of improvement

Proactive intervention:Human and proactive intervention through construction equipment

Passive Improvement:Through the thermal inertia of the building envelope, through better use of nature and the building itself without relying on building equipment to intervene

Passive means of improvement

Avoid the short board effect to strengthen the thermal insulation capacity:For the thermal insulation performance of the building, the thermal insulation capacity of the building envelope is determined by the worst part of the thermal insulation performance. The glass in the window is the weakest part of the thermal capacity of the building and should be specially designed. In addition, it is necessary to avoid the construction cold bridge caused by various unreasonable designs.

Enhancement of heat-taking capacity through the greenhouse effect:"Greenhouse effect" is a typical way of solar heat, in the cold winter should be reasonable application. There are two main types of building passive solar design: direct heat and indirect heat. Direct heat is obtained by storing solar radiation heat into various heat storage bodies of buildings, and then releasing them step by step at different times. Interthermal heat is a way to receive and store solar energy by heating various heat media, and then heat indoor air or various indoor heat storage bodies through heat media. Direct heat is the most effective and economical.

Enhancement of time lag effects through thermal storage design:The control of indoor temperature depends to a large extent on the configuration of insulation materials and heat storage materials. Reasonable setting will produce the phenomenon that the change of indoor temperature lags behind the change of outdoor temperature, which is the phenomenon of "time lag.

Set the climate buffer to control thermal comfort:The common climate buffer zone has the cold-proof door bucket, the closed balcony, the north side auxiliary room and so on.

Control and ventilation of indoor air convection using the chimney effect:Due to the difference in temperature and height, the air pressure difference will be caused, thus forming the movement of indoor airflow, called "chimney effect". In passive design, the chimney effect not only improves the thermal comfort of the building, but also has important significance for designing a healthy and clean indoor space.