HVAC Systems Proficiency Quiz

Relative humidity is calculated as the ratio of the amount of water vapor present in the air compared to the amount that would be present in the air when saturated at the same temperature. In this case, the relative humidity is 13%.

The dew point temperature can be calculated by finding the difference between the dry bulb temperature and wet bulb temperature. In this case, the difference is 100 degrees F - 65 degrees F = 35 degrees F. Therefore, the dew point temperature is 35 degrees F. This indicates the temperature at which air becomes saturated and dew forms.

When the wet bulb temperature equals the dry bulb temperature, the air is saturated with moisture, resulting in a relative humidity of 100%.

Comfort is often influenced by factors such as air quality, temperature, and humidity which contribute to a balanced environment for a person to feel comfortable.

When we sweat, the moisture on our skin evaporates, taking heat with it, thus cooling down the body. This process is known as evaporation.

Density of air is typically measured as the weight of air per unit volume, such as per cubic foot. It is a characteristic of the air's mass or weight in relation to the space it occupies, not the number of molecules, thickness, or temperature.

The dry bulb temperature refers to the temperature of the air without factoring in humidity or moisture content. It is a measure of the sensible heat level of the air.

The wet bulb temperature is an indicator that takes into account the moisture content in the air, making it a measure of humidity.

The wet bulb depression specifically refers to the difference between the temperature readings of the dry bulb and wet bulb of a thermometer, used to determine humidity and potential cooling effects.

The dew point temperature refers to the temperature at which air becomes fully saturated with water vapor, leading to the condensation of moisture. It is an important indicator of how much moisture is present in the air.

When the heat produced in the body is equal to the heat lost to the surroundings, the body maintains its ideal temperature, resulting in comfort. Therefore, the statement is true.

Forced ventilation in the winter heating season often brings in cold and dry air from the outside, which can actually lower the humidity level indoors, rather than raising it.

High head pressure in a window air conditioner is often caused by a dirty or blocked condenser. This reduces the efficiency of the unit and can lead to overheating.

The correct standard operating pressures for an R-22 window AC are 65 psig on the low side and 210 psig on the high side. These values are critical for optimal performance and efficiency of the system.

The amperage drawn by an air conditioning unit is determined by the product of power consumption (in watts) and voltage, divided by voltage. The higher the power consumption and the lower the voltage, the higher the amperage drawn.

Room air conditioners typically come in capacities ranging from 4,000 to 24,000 Btu/h to suit different room sizes and cooling needs.

The condensate off the evaporator coil in a room AC is typically drained to the slinger system of the fan to be dispensed off.

A heat pump room AC has a 4 way valve in addition to all the major components of a cooling unit. This valve allows for the reversing of the refrigerant flow direction, enabling both heating and cooling functions.

R-22 (also known as Freon) has been widely used as a refrigerant in room air conditioners, but due to its harmful effects on the environment, it is being phased out. R-134a, R-410A, and R-32 are alternative refrigerants that are more environmentally friendly and commonly used in modern air conditioning systems.

The round piece fastened to the outer tips of the condenser fan blade is known as the sling ring, which helps secure the blade in place and provide stability during operation. The other options, such as fan cap, blade guard, and spinner cap, do not accurately describe the specific part in question.

Most room AC units used in commercial buildings are sleeve mount style as they are specifically designed to fit into a sleeve in the wall, providing a more permanent and secure installation compared to window or portable units. Central AC systems are typically used in larger commercial buildings for whole-building cooling purposes.

Lowering the relative humidity of conditioned air involves the removal of moisture from the air, which is considered latent heat. Therefore, a window AC is indeed removing latent heat when decreasing the relative humidity.

In a domestic window AC, the condenser rejects more BTUs than the evaporator absorbs, making the statement false.

A dirty air filter can restrict the flow of air into the engine, leading to incomplete combustion and an increase in compression ratio.

Room AC units typically use a refrigeration cycle which involves a compressor and condenser coil to reject heat, rather than an evaporative condenser.

Not all 240 volt power supplies use the same style plug due to differing standards and requirements in various regions which can result in different plug types being used.

A reducing plenum system is designed to keep the velocity of air constant and the duct pressures constant in order to maintain proper airflow and pressure throughout the system.

The correct answer is 9 x 8 because it is the only dimension combination that meets both the airflow (250 cfm) and velocity (500ft/min) requirements based on standard duct design calculations.