Human Body And Thermal Comfort Quiz

Thermal comfort refers to the subjective state of satisfaction with the thermal environment. It is a personal experience that can vary from person to person and is influenced by various factors such as temperature, humidity, air velocity, and clothing. Some individuals may feel comfortable in a cooler environment, while others may prefer warmer conditions. Additionally, factors like activity level, personal preferences, and cultural background can also affect thermal comfort. Therefore, thermal comfort is a subjective experience that is influenced by individual and circumstantial factors.

The statement is true because the body has a narrow range of temperature within which it functions optimally. If the brain temperature falls outside this range, the body will initiate physiological responses to restore heat balance and bring the temperature back to the normal range. This is an important mechanism to ensure the proper functioning of the brain and overall homeostasis in the body.

The unit of measurement used to define power, which is the amount of energy consumed over a period of time, is called a watt.

Heat is transported around the body by the blood. The circulatory system, which includes the heart and blood vessels, plays a crucial role in distributing heat throughout the body. As blood flows through the body, it absorbs heat from areas with higher temperatures and carries it to areas with lower temperatures, helping to maintain a stable body temperature. Additionally, blood vessels near the surface of the skin can dilate or constrict to regulate heat loss or retention, further assisting in heat distribution.

The temperature of the internal organs, including the brain, needs to be maintained constant at around 37°C for the proper functioning of the body. This temperature is considered normal and optimal for the organs to carry out their essential functions efficiently. Deviations from this temperature can lead to various health issues and can disrupt the normal functioning of the organs.

The four environmental conditions that allow heat to be lost from the human body are air temperature, humidity, air velocity, and mean radiant temperature (MRT). These factors play a crucial role in creating thermal comfort. Air temperature refers to the temperature of the surrounding air, which affects how much heat the body can dissipate. Humidity refers to the amount of moisture in the air, which can impact the body's ability to cool down through sweat evaporation. Air velocity refers to the movement of the air, which can enhance or hinder heat loss. Mean radiant temperature (MRT) refers to the average temperature of the surrounding surfaces, which can affect the body's heat exchange through radiation.

The brain is the controlling mechanism for various functions in the body. It is responsible for processing sensory information, coordinating movements, regulating body temperature, and controlling emotions and behavior. The brain is made up of different regions, each with specific functions, and it communicates with the rest of the body through the nervous system. Therefore, it is logical to conclude that the brain is the controlling mechanism mentioned in the question.

Air movement affects the heat-loss rate by both convection and evaporation. Convection is the transfer of heat through the movement of air or fluid. When air moves across a surface, it carries away the heat from that surface, resulting in faster heat loss. Evaporation is the process of converting a liquid into a gas, and it requires heat energy. When air is moving, it increases the rate of evaporation, which also contributes to heat loss. Therefore, both convection and evaporation play a role in how air movement affects the heat-loss rate.

The term "biological machine" accurately describes the human body in the given context. It highlights the fact that the human body functions like a machine, converting food into energy and producing heat as a byproduct. The mention of "burning food as fuel" and "generating heat" aligns with the idea of the body as a machine. Additionally, the statement about exhaling warm moist air and losing heat through the skin further emphasizes the body's mechanism of heat regulation, which is a characteristic of a machine-like system.

The skin regulates the heat flow by controlling the amount of blood flowing through it. The blood vessels in the skin can dilate or constrict to regulate the amount of blood reaching the surface of the skin. When the body needs to cool down, the blood vessels dilate, allowing more blood to flow through the skin and release heat. Conversely, when the body needs to conserve heat, the blood vessels constrict, reducing the amount of blood flow to the skin and minimizing heat loss.

Relative humidity is a measure of the amount of moisture present in the air compared to the maximum amount of moisture the air can hold at a specific temperature. It is expressed as a percentage and indicates how close the air is to being saturated with water vapor. A higher relative humidity means the air contains more moisture, while a lower relative humidity indicates drier air.

The rate at which heat is lost to the air is determined by the air temperature. This is because heat naturally flows from a higher temperature to a lower temperature. Therefore, if the air temperature is higher, the rate of heat loss will be faster compared to when the air temperature is lower.

The explanation for the given answer is that a comfort wind less than 1.5% is acceptable. For example, a temperature of 37°C with 5% humidity is acceptable, as well as a wind speed of 1.5%.

The human body gains heat primarily through metabolism. Metabolism refers to the chemical processes that occur within the body to maintain life. These processes produce heat as a byproduct, which helps to regulate body temperature. Therefore, metabolism is the main mechanism by which the body generates heat.

If the temperature rises above 41°C or falls below 30°C, death is imminent. This suggests that extreme temperatures can be fatal.

Mean Radiant Temperature refers to the average temperature of all the objects in the surroundings that emit or reflect thermal radiation towards a body. It takes into account the size and temperature of each object, and calculates a weighted average based on the area of each object. This measurement is important in determining the thermal comfort of a person, as it affects the heat exchange between the body and its environment.

The psychrometric chart is a powerful tool used to analyze and understand the relationship between temperature, humidity, and human comfort. It provides a visual representation of how these factors interact and affect the thermal comfort of individuals. By using this chart, one can determine various properties such as relative humidity, dew point temperature, and enthalpy. It is commonly used in fields such as HVAC engineering, meteorology, and building science to design and evaluate indoor environments for optimal comfort.

Convection is the process of heat transfer through the movement of molecules in a fluid (air or liquid). When a surface is heated or cooled, the molecules near the surface gain or lose energy and become less dense. This causes them to rise or sink, creating a flow of fluid. As the fluid moves, it carries heat with it, transferring it from one region to another. This process is known as convection heat transfer.

The given question is asking for the range of the internal comfort temperature. The range is indicated by the two blanks. The first blank represents the lower limit of the temperature range, which is 20˚C. The second blank represents the upper limit of the temperature range, which is 24˚C. Therefore, the correct answer is 20,24.

Saturation humidity refers to the maximum amount of water vapor that air can hold at a given temperature and pressure. It is measured in grams of water vapor per kilogram of air (g/kg). When the air reaches its saturation point, it cannot hold any more moisture, resulting in the formation of clouds or precipitation. Saturation humidity is an important concept in meteorology and is used to understand and predict weather patterns.

The measure of the effect of moisture in an air-vapor mixture is the wet-bulb temperature. This temperature is determined by using a thermometer with a wetted bulb that is rapidly moved through the air, which promotes evaporation. The rate of evaporation is influenced by the amount of moisture present in the air, and this affects the cooling effect on the wet bulb. Therefore, the wet-bulb temperature provides an indication of the humidity level in the air-vapor mixture.

Humidity refers to the amount of moisture present in the air. It is a measure of the water vapor content in the atmosphere. High humidity indicates that the air has a high moisture content, while low humidity indicates a lower moisture content. Humidity is an important factor in weather conditions and can affect human comfort, as well as various natural processes such as evaporation, condensation, and precipitation.

The specific volume (reciprocal of density) of the air-vapour mixture is indicated by another set of slightly more sloping lines on the psychrometric chart. This means that as the specific volume increases, the density decreases. The specific volume represents the volume occupied by a unit mass of the mixture, so a higher specific volume indicates that the mixture is less dense and takes up more space per unit mass. The slightly more sloping lines on the psychrometric chart indicate this relationship between specific volume and density.

Wet Bulb Depression Lines refer to the difference in temperatures between the wet wick thermometer and the Dry Bulb Temperature (DBT). This measurement is used to determine the level of humidity in the air. The wet wick thermometer is wrapped in a wet cloth and as the water evaporates, it cools down the temperature. The difference between the wet wick thermometer and the DBT indicates how much evaporation is occurring, which in turn reflects the humidity level. Wet Bulb Depression Lines are used to plot this temperature difference on a graph, allowing for a visual representation of humidity levels.

The DBT (Dry Bulb Temperature) corresponding to this point is referred to as the dew-point temperature of the original atmosphere. If there is further cooling, the status point will move along the saturation line and condensation will occur. The dew-point temperature is the temperature at which air becomes saturated and can no longer hold all of its water vapor, resulting in the formation of dew or condensation.