What's the indoor temperature? How comfortable is the human body?

In winter, 80% people feel comfortable in the temperature range of 17 ~ 19.2℃. When the indoor temperature is 18℃, half of people will feel cold when sitting; When the temperature is below 12℃, 80% people will feel cold when sitting, some people will feel uncomfortable, and more than 20% people who are active will feel cold. The temperature that makes people feel lukewarm is called "physiological zero". Physiological zero is the most comfortable temperature for people. Different people have different physiological zero degrees, and the physiological zero degree of normal people is about 28 ~ 29℃. After long-term research, observation and comparison by scientists, it is considered that the ideal indoor temperature in life should be: when the relative humidity is controlled at 30% ~ 40% and the temperature is kept at 24℃, people feel most comfortable indoors at this time.

Low ambient temperature can increase muscle tension and energy metabolism; Excessive ambient temperature can strengthen the metabolism of substances in the body and increase energy metabolism. The difference between the thermal change process of human body and non-living body is that the temperature and heat dissipation of human body are not completely determined by environmental factors, because the temperature regulation system of human body has the ability to actively adjust these parameters within a certain range of environmental parameters. Compared with inanimate objects, warm-blooded animals, including humans, have a perfect thermoregulation mechanism, which depends on the regulation of nerves and body fluids. When the external environment temperature changes, the body temperature can be kept relatively stable by adjusting the heat generation and heat dissipation process.

In order to maintain a comfortable indoor temperature, air conditioners are installed at home or in the office. In order to save energy and reduce greenhouse gas emissions, our government requires that the air conditioning temperature of public buildings should be controlled above 26℃. According to estimates, if the air conditioning temperature increases by 2℃ during cooling, it can save 20% electricity, and it will not have a great impact on human comfort. The difference between the surface water temperature in the South China Sea in China and the water temperature at a depth of 800 meters is often used to describe the ocean, which actually reflects the huge energy contained in the ocean. Can we use these energies of the ocean effectively?

Ocean energy includes tidal energy, wave energy, ocean current energy, seawater temperature difference energy and salinity difference energy. Except tidal energy comes from the gravity of the moon and the sun, other energy is converted from solar radiation, which belongs to permanent, clean and renewable energy.