Understanding the ESCO Air Conditioning Exam: A Practice Question Breakdown

If 10 pounds of refrigerant pass through a water-cooled condenser losing 20 BTUs of heat per pound, and 10 pounds of water enter at 80°F, what is the temperature of the water leaving the condenser?

• A. 90°F
• B. 95°F
• C. 100°F
• D. 105°F

Answer: (C)

To determine the temperature of the water leaving the condenser, you need to calculate how much heat is absorbed by the water due to the refrigerant losing heat in the condenser. First, calculate the total heat removed from the refrigerant. If 10 pounds of refrigerant lose 20 BTUs per pound, you multiply the mass of the refrigerant by the heat loss per pound: Total heat loss = 10 pounds × 20 BTUs/pound = 200 BTUs. This 200 BTUs is what the water will absorb as it flows through the condenser. Next, consider the water entering the condenser at 80°F. To find the temperature of the water leaving the condenser after absorbing the heat, we can use the formula for heat transfer, which is: Heat absorbed = mass of water × specific heat of water × change in temperature. Assuming we're dealing with typical water properties, the specific heat of water is about 1 BTU per pound per °F. Given that we have 10 pounds of water, we can rearrange the formula to find the change in temperature: 200 BTUs = 10 pounds × 1 BTU/pound/°F × (T_final - 80°F). Let T_final represent

In preparation for the ESCO Air Conditioning Exam, you may find yourself grappling with a variety of concepts, especially those related to refrigeration. Today, let's unpack a practice question that revolves around a water-cooled condenser—an essential component in many HVAC systems.

So, picture this: you have 10 pounds of refrigerant flowing through a water-cooled condenser. Each pound loses 20 BTUs of heat. Meanwhile, 10 pounds of water enters the condenser at a temperature of 80°F. Sounds like a mouthful, right? But don’t worry, we’re breaking it down nicely!

First off, understanding BTUs is crucial here. A BTU (British Thermal Unit) measures the heat needed to raise the temperature of one pound of water by one degree Fahrenheit. Often, when we deal with HVAC systems, knowing how much heat is being transferred is fundamental.

Now, if we calculate the total heat being removed from the refrigerant, we simply take the weight and multiply it by the heat loss per pound:

[ 10 , \text{pounds} \times 20 , \text{BTUs/pound} = 200 , \text{BTUs}.]

This represents how much heat the refrigerant is giving off to the water in the condenser. By transferring this heat, the refrigerant cools down, making way for its cycle to continue efficiently.

Next, let’s figure out how this impacts our entering water. Since 10 pounds of water entered at 80°F and we're removing 200 BTUs of heat from it, we can determine how much the temperature of this water will rise. Because we know that the specific heat capacity of water is 1 BTU/(lb °F), we apply our new-found knowledge:

[ \frac{200 , \text{BTUs}}{10 , \text{pounds} \times 1 , \text{BTU/°F}} = 20°F. ]

This means the water's temperature increases by 20°F. As such, when you leave the condenser, the water temperature will be calculated as follows:

[ 80°F + 20°F = 100°F. ]

So when posed with the original question on the exam, the correct answer is C—100°F.

Now, isn’t it fascinating how these seemingly complicated calculations break down into manageable parts? It highlights the essence of HVAC—balancing heat transfer effectively not only keeps systems running smoothly but also shows how physics applies in everyday life.

Moreover, tackling questions like this helps us solidify our understanding in preparation for the ESCO Air Conditioning Exam. By studying scenarios involving different temperatures, capacities, and heat transfers, you’re not just memorizing; you’re learning to think critically about how air conditioning systems operate.

So here’s the takeaway: don't shy away from these practice questions. Embrace them! They not only enhance your technical skills but also prepare you for practical situations in the field. You know what? Practicing these calculations can make all the difference when you’re hands-on with air conditioning units later down the line.

Remember, whether it’s water-cooled condensers or other components, every question answered successfully inches you closer to conquering that exam. Happy studying!