Discover Q&A generated by AI Answer Generator

The three main components of HVAC systems typically include:

A. Source
C. Air side
D. Distribution

However, it's important to note that "Water side" and "Terminal" can also be considered components in specific contexts, especially in systems that utilize water for heating or cooling.

So, the most common selections would be A, C, and D, but depending on the specific HVAC system being discussed, B and E could also be relevant.

D. Reversing valve

The reversing valve is typically found in heat pump systems, which can operate in both heating and cooling modes. In a standard refrigeration cycle, the main components are the compressor, condenser, and evaporator.

A Variable Air Volume (VAV) box regulates the temperature of a space primarily by:

B. Adjusting the flow of air into the space.

VAV boxes control the amount of conditioned air delivered to a space based on the temperature requirements, allowing for efficient temperature regulation without the need for constant reheating or mixing of air.

The abbreviation CV in valves means D. Flow Coefficient. The flow coefficient (CV) is a measure of the capacity of a valve to allow fluid flow.

To calculate the volume of air flowing through a duct, you need at least the following measurements:

A. Velocity pressure
D. Duct area

These two measurements allow you to determine the air velocity and then calculate the volumetric flow rate (volume per unit time) using the duct area.

While air temperature and duct shape can be important for other calculations (like density or pressure drop), they are not strictly necessary for calculating the volume flow

A device that measures the moisture content in the air is called a:

A. Hygrometer

While "humidimeter" is sometimes used, "hygrometer" is the more commonly accepted term.

C. Either can be placed on the inlet of a coil.

Both mixing and diverting valves can be used on the supply water side of a coil, depending on the specific application and system design requirements.

A controller that only allows certain parameters to be adjusted is called a D. Configurable Controller.

In a refrigeration cycle, the heat transfer devices are primarily the components that facilitate the transfer of heat from one medium to another. Based on the options provided, the correct selections are:

B. Condenser - This device removes heat from the refrigerant as it condenses from a gas to a liquid.

C. Evaporator - This device absorbs heat from the environment (or the space being cooled) as the refrigerant evaporates from a liquid to a gas.

The other options, A (Compressor) and D (Expansion Device), are important components of the refrigeration cycle but do not directly transfer heat. The compressor compresses the refrigerant and increases its pressure, while the expansion device reduces the pressure of the refrigerant.

So, the correct answers are:

• B. Condenser
• C. Evaporator

The correct answer is C. Latent heat.

Latent heat is the heat added or removed from a substance during a phase change (such as from liquid to gas) without a change in temperature. In this case, as water changes to steam at 212°F (100°C), it absorbs latent heat.

A. Absorption

Absorption chillers do not use a mechanical compressor. Instead, they use a heat source to drive the cooling process, typically utilizing a refrigerant and an absorbent solution. The other options (reciprocating, scroll, and centrifugal chillers) all use compressors as part of their refrigeration

Comfort problems will likely be experienced if zone temperature sensors are mounted in the following locations:

A. In direct sunlight
B. On an exterior wall
C. Behind an obstruction such as a door or bookcase

These locations can lead to inaccurate temperature readings, which can affect the heating and cooling system's performance and overall comfort in the space.

D. On an interior wall away from heat gains is generally a better location for a temperature sensor, as it is less likely to be influenced by external temperature fluctuations or ob

The correct answer is C. Mixing Box. A mixing box is designed to blend cold and hot air streams while also helping to reduce noise associated with the mixing process.

When setting a minimum ventilation value of 20% on an Air Handling Unit (AHU) and commanding a 20 percent opening of the parallel blade outdoor air damper, the following outcomes can be expected:

A. A 20 percent flow through the damper - This is correct. A 20 percent command to the damper should theoretically allow 20 percent of the maximum airflow through the damper.

B. Greatly over ventilating the space - This is not correct. A 20 percent damper opening should not lead to over-ventilation if the system is designed for that minimum ventilation requirement.

C. Excessive loads on the boiler in the winter and chiller in the summer - This could be correct. If the damper is allowing outdoor air in at a rate that is not balanced with the system's heating and cooling capacity, it could lead to excessive loads on the heating and cooling systems.

D. Unnecessarily increasing the owner’s utility bills - This is also correct. If the system is not properly balanced and is bringing in more outdoor air than necessary, it can lead to increased energy consumption and higher utility bills.

Therefore, the correct answers are **A, C,

D. Heat exchanger

A. TRUE

Damper authority refers to the ability of a damper to control the flow of air in a system, and it does contribute to the volume of mixed air flow in an air handler. Proper damper authority ensures that the desired amount of outside air and return air is mixed effectively to maintain the desired indoor air quality and temperature.

The correct answer is A. Sensible heat.

Sensible heat refers to the heat that causes a change in temperature of a substance without changing its state (phase). In this case, since the water in the pipe has not changed state (remains liquid), the change in temperature is due to sensible heat.

In an air duct, if the pressure increases from 0.7 inches of Water Column to 1 inch of Water Column with no change in input air, you would generally assume that the temperature would go down (C).

This is based on the principles of thermodynamics and the ideal gas law, which states that for a given amount of gas at constant volume, an increase in pressure can lead to a decrease in temperature if no additional heat is added to the system. In practical terms, as the air is compressed (increased pressure), it can lead to a cooling effect if the system is not insulated or if there is no heat input.

However, it's important to note that real-world scenarios can be influenced by various factors, including heat transfer, humidity, and the specific conditions of the air

In CSS code, any text between /* and */ is treated as a comment and ignored by user agents.

So the correct answer is: d. / and /

The correct answer is c. rel.

In HTML, the rel attribute is used in the <link> element to specify the relationship between the current document and the linked document, such as a stylesheet. The type attribute can also be used to specify the type of the linked document, typically set to "text/css" for CSS stylesheets.

The correct answer is:

d. inline

Tim should use a. > between the elements in his selector to indicate that an element is a direct child of another element.

For example, if you want to select all <p> elements that are direct children of a <div>, you would write the selector as div > p.

The correct answer is b. last.

In CSS, if multiple rules apply to the same element and specify values for the same attribute, the value from the last rule in the style sheet takes precedence, assuming the rules have the same specificity.

Tim quickly changes his strategy and uses a b. class attribute instead.

In HTML, the id attribute must be unique within a page, while the class attribute can be assigned to multiple elements, allowing for shared