Consider a “cold” winter day in with an air temperature of 7.22 °C and relative humidity...
Consider a “cold” winter day in with an air temperature of 7.22 °C and relative humidity of about 20% (moisture content 0.001 g H2O/g dry air). A person waiting at a bus stop inhales at an average rate of 8 g dry air/min and exhales air saturated with water at body temperature (37°C) and 1 atm (molal humidity is 6.7%). The heat capacity of dry air is 1.05 J/g- °C. Estimate the rate of heat loss from breathing. Express your answer in units of kcal/hr. Hint: ‘molal humidity’ = moles of water vapor / moles of vapor-free (dry) gas
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Consider a “cold” winter day in with an air temperature of 7.22
°C and relative humidity...
a) Define relative humidity (2 marks) b) Describe the relation between relative humidity, the capacity of...
a) Define relative humidity (2 marks) b) Describe the relation between relative humidity, the capacity of air to hold moisture a ambient temperature. (2 marks) c) Moist air at 22°C and a wet bulb temperature of 9°C enters a steam spray humidifier. The mass flow of the dry air is 90 kg/min. Saturated water vapor at 110 °C is injected into the mixture at a rate of 52 kg/hr. There is no heat transfer with the surroundings, and the pressure...
150 ft3/min of air at 80F dry-bulb temperature and 70% relative humidity enters an air conditioning...
150 ft3/min of air at 80F dry-bulb temperature and 70% relative humidity enters an air conditioning unit and leaves it as saturated air at 50F. Part of the moisture in the air that condensate is collected and removed at 55F. Draw the cycle on the attached chart and a)Determine the rates of heat removal from the air. b)Determine the rate of moisture removal from the air
Humidity is the amount of water vapor in the air at a given time
Humidity is the amount of water vapor in the air at a given time. At warm temperatures, air can hold more moisture than it can at cold temperatures. Relative humidity is the amount of vapor the air is holding expressed as a percentage of the amount the air is capable of holding. For example, at 86 degrees Fahrenheit, air can hold a maximum of 30.4 grams of water per cubic meter. If the air at the same temperature is holding...
3. The air in a building is to be maintained at 25°C and 55% relative humidity...
3. The air in a building is to be maintained at 25°C and 55% relative humidity by passing outside air through a water spray. The air enters the spray chamber at 32°C and 70% relative humidity, leaves the chamber cooled and saturated with water vapor, and is then reheated to 25°C. Estimate the temperature of the air leaving the spray chamber and the water (kg) added to or removed from (specify which) each kilogram of dry air processed
9. A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity....
9. A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a dry, heating climate: a. 32°F dry bulb temperature and 40% relative humidity (winter conditions) b. 90°F dry bulb temperature and 20% relative humidity (summer conditions) DO
The atmospheric air 32 °C dry bulb temperature and 70% relative humidity supplied to the cooling...
The atmospheric air 32 °C dry bulb temperature and 70% relative humidity supplied to the cooling coil at a rate of 45m3/min. The air cooling to the saturated state and leaving at a temperature of 16 °C. Determine: a- Specific humidity at each state. b- Wet bulb and dew point temperatures at the final state c- Final relative humidity. d- Mass of water condensed. e- Rate of heat removed from the air in kW. f- Show the process on Psychrometric...
11-35.A moist air mixture with a dry bulb temperature of 48°C, a relative humidity of 40...
11-35.A moist air mixture with a dry bulb temperature of 48°C, a relative humidity of 40 percent, and a total pressure of 160 kPa is contained in a rigid vessel having a volume of 1.65 m3. The air is cooled until the dry bulb temperature reaches 23°C. Determine the amount of heat transferred, the final pressure of the air, and the amount of water vapor condensed during the process.
- Air at a temperature of 20 0C and 750 mm Hg has a relative humidity...
- Air at a temperature of 20 0C and 750 mm Hg has a relative humidity of 80%. Calculate, (i)The molal humidity of the air (ii)The molal humidity of this air if its temperature is reduced to 10 °C and pressure increased to 2000 mm Hg condensing out some of the water (iii)Weight of water condensed from 1000 litre of the original wet air Vapour pressure of water at 20 °C = 17.5 mm Hg Vapour pressure of water at...
The weather report indicates that the temperature outside is 15°C with a relative humidity of 75%....
The weather report indicates that the temperature outside is 15°C with a relative humidity of 75%. Using this information, provide the following: a) Wet bulb temperature b) Dew point temperature c) Moisture content of the outside air d) Specific volume of the outside air e) Enthalpy of the outside air f) How much moisture would you need to add to the air in order to saturate it? (Give this answer in kg moisture/kg dry air). g) The air temperature in...
1. (relative humidity) The partial pressure of water vapor in air is usually less than the...
1. (relative humidity) The partial pressure of water vapor in air is usually less than the equilibrium vapor pressure (or saturation pressure) at the ambient temperature; this is why a cup of water will spontaneously evaporate. The ratio of the partial pressure of water vapor to the equilibrium vapor pressure (at the same temperature) is called the relative humidity. Saturated air, at 100% relative humidity, would be in equilibrium with a cup of liquid water. The saturation pressure depends strongly...
a) Define relative humidity (2 marks) b) Describe the relation between relative humidity, the capacity of air to hold moisture a ambient temperature. (2 marks) c) Moist air at 22°C and a wet bulb temperature of 9°C enters a steam spray humidifier. The mass flow of the dry air is 90 kg/min. Saturated water vapor at 110 °C is injected into the mixture at a rate of 52 kg/hr. There is no heat transfer with the surroundings, and the pressure...
3. The air in a building is to be maintained at 25°C and 55% relative humidity by passing outside air through a water spray. The air enters the spray chamber at 32°C and 70% relative humidity, leaves the chamber cooled and saturated with water vapor, and is then reheated to 25°C. Estimate the temperature of the air leaving the spray chamber and the water (kg) added to or removed from (specify which) each kilogram of dry air processed
9. A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a dry, heating climate: a. 32°F dry bulb temperature and 40% relative humidity (winter conditions) b. 90°F dry bulb temperature and 20% relative humidity (summer conditions) DO
11-35.A moist air mixture with a dry bulb temperature of 48°C, a relative humidity of 40 percent, and a total pressure of 160 kPa is contained in a rigid vessel having a volume of 1.65 m3. The air is cooled until the dry bulb temperature reaches 23°C. Determine the amount of heat transferred, the final pressure of the air, and the amount of water vapor condensed during the process.
The weather report indicates that the temperature outside is 15°C with a relative humidity of 75%. Using this information, provide the following: a) Wet bulb temperature b) Dew point temperature c) Moisture content of the outside air d) Specific volume of the outside air e) Enthalpy of the outside air f) How much moisture would you need to add to the air in order to saturate it? (Give this answer in kg moisture/kg dry air). g) The air temperature in...
1. (relative humidity) The partial pressure of water vapor in air is usually less than the equilibrium vapor pressure (or saturation pressure) at the ambient temperature; this is why a cup of water will spontaneously evaporate. The ratio of the partial pressure of water vapor to the equilibrium vapor pressure (at the same temperature) is called the relative humidity. Saturated air, at 100% relative humidity, would be in equilibrium with a cup of liquid water. The saturation pressure depends strongly...
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