HPAC 2021: Our Monthly Quiz

The heating, piping, and air conditioning industry has been a fixture of ‘civilized’ life on Planet Earth for well over a century, and the focus of this venerable publication since 1929. The inventive and problem-solving work of engineers, manufacturers, and building owners have continuously helped to expand the impact of the HVACR industry beyond creature comforts and food and data storage to life and death issues like greenhouse gas reductions and, especially today, virus mitigation.

 

With all that in mind, HPAC Engineering here welcomes you to join us on a fun monthly ride through the milestones, innovations, people, places, problems and products that have come to define this industry and your work. Hopefully, there may even be a chuckle or two along the way. So, here goes, and see below for your chances to win a $50 Amazon gift card.

Photo Credit: Thinkstock
This spring, as new engineering school graduates celebrate across the land, and professional licensing exams start to enter their post-party consciousness, we take a moment to preview some questions that may be awaiting them. With the assistance of Honolulu-based test prep service Engineering Pro Guides, here are five problems that could come up on future jobs. First off, let’s say you are designing an HVAC system at an elevation 7,500 ft above sea level. With outside air conditions of 60° F DB and 90% RH, what will be the density and dew point of the outside air?

0.0631 lb/ft3 and 57.1 F dp 

0.0631 lb/ft3 and 60.0 F dp 

{{CorrectAnswer01}}

0.0759 lb/ft3 and 55.1 F dp 

Photo credit: Arizona State University

An air handler supplies 5,000 CFM at a temperature of 55° F. The air handler was designed for 1,000 CFM of outside air at 87° F DB and 78° F WB. The remaining return air from the space is at 77° F DB and 55% relative humidity. What are the entering conditions of the air into the coil, in DB and WB?

{{CorrectAnswer02}}

79° F DB, 59.6° F WB 

85° F DB, 74.3° F WB 

85° F DB, 75.7° F WB 

Photo credit: Daikin Applied

The air handler serving the classroom has a supply air temperature of 55° F and the space is to be maintained at 75° F DB and 50% Relative humidity. What CFM is required? 

{{CorrectAnswer03}}

2,675 CFM 

2,790 CFM 

3,865 CFM 

Photo credit: iStock

An existing chiller is served by a chilled water pump (150 GPM, 75 TDH), 65% efficient pump, 90% efficient motor. A recent study found that the pump was oversized and should be replaced with a new, higher efficiency pump at 150 GPM, 50 TDH, 80% efficient pump and 95% premium efficiency motor. If the pump runs 8 hours a day, 5 days a week, 52 weeks a year, how many kWh per year will be saved by switching to the new pump? 

7,250 kWh 

4,150 kWh 

3,990 kWh 

{{CorrectAnswer04}}

Photo credit: Carrier Corp.
A new steam boiler provides 100 lb/hr of steam at 30 PSIA, 0 degrees super heat to various hot water heaters. If the hot water heaters are designed to provide a 40 degree delta to incoming water at 80° F, then what is the total GPM of hot water that the boiler can support?

10.2 GPM 

15.7 GPM 

{{CorrectAnswer05}}

21.9 GPM 

Photo credit: ABMA