The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is: At t = 35°C = Psat = 5.6286 kPa

If the sensible heat ratio is 0.80 and the cooling load is 100 kW, what is the amount of sensible heating?

Answer:

A coil has an inlet temperature of 60 °F and outlet of 90 °F. If the mean temperature of the coil is 110 °F, find the bypass factor of the coil.

If the latent and sensible heat loads are 20 kW and 80 kW respectively, what is the sensible heat ratio?

Answer:

Answer:

A rectangular duct has a dimension of 0.25 m by 1 m. Determine the equivalent diameter of the duct.

Wet material containing 215 % moisture (dry basis) is to be dried at the rate of 1.5 kg/s in a continuous dryer to give a product containing 5 % moisture (wet basis). The drying medium consist of air heated to 373 K and containing water vapor equivalent to a partial pressure of 1.40 kPa. The air leaves the dryer at 310 K and 70 % saturated. Calculate how much air will be required to remove the moisture.

In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?

Answer:

A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.

Air at normal atmospheric pressure has a temperature of 70 ̊F and a dew point temperature of 50 ̊F. Determine the saturation ratio of the air. The humidity ratios corresponding to dew point temperatures of 50 ̊F and 70 ̊F respectively are 0.00763 lb/lb and 0.01576 lb/lb respectively.

Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.

If the total heat removed per pound of dry air is 10 BTU and the sensible heat removed per pound of dry air is 6 BTU. Compute the sensible heat factor (SHR).

Determine the approximate load on a cooling tower if the entering and leaving temperatures are 96 ̊F and 88 ̊F, respectively and the flow rate of the water over the tower is 30 gpm.

The mass of an outside air at 50 ̊C in an air conditioning unit is 60 kg. Find the temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35 ̊C.

How do you call the water vapor content of air?

Answer:

A natural draft cooling tower has a 400-ton heat rejection load. The tower operates at an efficiency of 52 % when the outdoor wet-bulb temperature is 75 ̊F and the entering water temperature is 90 ̊F. The temperature of the water leaving the tower is:

Air at 80 ̊F dry-bulb and 67 ̊F wet-bulb temperature enters a 42 ̊F cooling oil and leaves at 53 ̊F dry-bulb. Then the air is reheated to 66 ̊F. The cooling efficiency is:

When air contains all of the water vapor it can hold, it is said to be ________.

What is the instrument used to register relative humidity?

Humidity is a measure of which of the following?

In an air conditioning system, before the air is circulated to the required area, it is:

The temperature at which water vapor in the atmosphere begins to condense is known as the:

Saturation temperature is the same as;

When the bypass factor is B, the coil efficiency for sensible cooling of air is equal to:

The psychrometric chart in air conditioning determines the _______________.

What is the value of air stratification in air conditioning design fit for human comfort?

Which of the following statement is correct? The relative humidity of an air water vapor mixture ______________.

In sensible cooling process, moisture content.

What amount of air is required in a low bypass factor?

What is the lowest temperature to which water could possibly be cooled in a cooling tower?

Combined process of cooling and humidifying is also known as:

In a cooling tower, the water is cooled mainly by _________.

Which of the following types of air dryers works by absorbing moisture on a solid dessicant or drying material such as activated alumina, silicon gel or molecular sieve?

The relationship of water vapor in the air at the dew point temperature to the amount that would be in the air if the air were saturated at the dry bulb temperature is:

A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of dry air in the room.

A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of the water vapor in the room.

A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. What is the dew point temperature, ̊F.

When the air is saturated the wet bulb depression is _____________.

A temperature measurement in an ordinary thermometer which has constant specific humidity.

During sensible heating, the humidity remains constant but the relative humidity.

The relative humidity becomes 100 % and where the water vapor starts to condense.

What is the specific humidity of dry air?

What is the temperature range of air in air conditioning application where the dry air can be considered ideal gas?

In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?

A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.

Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.

The relative humidity becomes 100 % and where the water vapor starts to condense.

Why should you avoid bending or twisting of fan blades in an air conditioning unit?

A type of refrigerant that will not damage the ozone layer.

Which of the following is the type of refrigerant that damages the ozone layer?

The phenomenon that warm air rise and cold air settle is called:

Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or more is called:

Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.

From what principle that air ducts operate?

It is used to deliver concentrated airstreams into a room. Many have one-way or two- way adjustable air stream deflectors.

It is used to control the air-throw distance, height, and spread, as well as the amount of air.

It is used to deliver widespread, fan-shaped flows of air into the room.

Which of the following fans in air conditioning systems which can be classified as centrifugal flow?

The most common controller in the heating and cooling systems.

A thermostat that functions as increase or decrease instead of starting and stopping system is called:

A number used to compare energy usage for different areas. It is calculated by dividing the energy consumption by the fottage of the conditioned area.

The ratio of the rated cooling capacity divided by the amount of electrical power used:

Heat exchanger in which water flows by gravity over the outside of the tubes or plates.

The relative humidity becomes 100 % and where the water vapor starts to condense.

Why should you avoid bending or twisting of fan blades in an air conditioning unit?

A type of refrigerant that will not damage the ozone layer.

Which of the following is the type of refrigerant that damages the ozone layer?

Large-bulb alcohol thermometer used to measure air speed or atmospheric conditions by means of cooling.

The phenomenon that warm air rise and cold air settle is called:

Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or more is called:

Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.

From what principle that air ducts operate?

Which of the following is the common classification of ducts?

It is used to deliver concentrated airstreams into a room. Many have one-way or two- way adjustable air stream deflectors.

It is used to control the air-throw distance, height, and spread, as well as the amount of air.

It is used to deliver widespread, fan-shaped flows of air into the room.

Which of the following fans in air conditioning systems which can be classified as centrifugal flow?

The most common controller in the heating and cooling systems.

Copra enters a dryer containing 60 % water and 40 % of solids and leaves with 5 % water and 95 % solids. Find the weight of water removed based on each pound of original product.

The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is:

In an auditorium maintained at a temperature not to exceed 24℃ and relative humidity not to exceed 60 %, a sensible heat load of 132 kW and 78 kg moisture per hour to be removed. Air is supplied to the auditorium at 18℃. How many kilograms of air must be supplied per hour?

A room contains air at 27 ℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm. The humidity ratio is most nearly equal to:

A room contains at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm. The enthalpy is most nearly _______.

A room contains air at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm. The specific heat is most nearly _______.

The temperature to which the air must be cooled at constant pressure to produce saturation is called:

A refrigerating plant for an air conditioning system is to have a capacity of 10 tons and a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4 Btu/lb of refrigerant. Calculate the compressor internal horsepower, hp

The mass of water vapor per unit volume of air ______________.

The heat transfer due to motion of matter cause by a change in density is called:

A newly designed isolation room that is to contain 40 people is to air-conditioned with window air-conditioning units of 5 kW cooling capacity. A person at rest may dissipate heat at the rate of 360 kJ/hr. The room has 10 lightbulbs with each rating of 100 watts. If the rate of heat transfer to the room walls and windows is estimated to be 15,000 kJ/hr and the room air is to be maintained at a constant temperature of 21 ℃, calculate the number of window air-conditioning units required.

The changing of solid directly to vapor, without passing through the liquid state is called:

Answer:

What amount of air is required in a low bypass factor?

Determine the partial pressure of water vapor if the barometric pressure is 101.325 kPa and the humidity ratio is 0.05.

Pump used to increase air pressure above normal, air is then used as a motive power.

An old auditorium has a seating capacity of 1500 people and is to be maintained at 80 ℉ (𝐷𝐵) and 65℉ (𝑊𝐵) when the outdoor air is at 91 ℉ (𝐷𝐵) and 75℉ (𝑊𝐵). Calculate the quantity of the supply of air at 60℉ given that the solar heat is 110,000 Btu/hr, note: Sensible heat per person is 225 Btu/hr

Ten pounds of air at a dry bulb temperature of 50℉ with a specific humidity of 40 grains/lb dry air are mixed with 25 lb of air having a temperature of 85 ℉ and a specific humidity of 90 grains/lb dry air. Calculate the enthalpy of the mixture, Btu/lb dry air.