Author: Kevin Jensen

I have written before on how construction documents are drawn using computer software, but I haven’t written much about how an engineer knows how big of an air conditioner to install in a building.  Using historical weather data and the building characteristics, the engineer simulates the building operating throughout the year to find the peak or max load and sizes the equipment based on that moment in (simulated) time.

Trane Trace 700, EnergyGauge, EnergyPro and EnergyPlus are all software packages that can simulate a building and estimate loads as well as energy usage.  Of course, the quality of the information coming out of the software relies heavily on the quality of the information going into the software.  The engineer must accurately input all the exterior walls and the roof by telling the program the size, the direction it is facing and the conductivity (how well heat passes through it) of each surface.  Lights, which give off heat, must be included in each space.  Any ventilation and exhaust airflow are also factored into the model.

The trickiest piece of the puzzle, however, are usually the people inside the building.  Since people give off quite a bit of heat this can be a significant part of the HVAC design.  A building may have a maximum occupancy, but it’s rarely completely full so the engineer uses a schedule to modify the number of people in a space to better estimate the actual load.  Careful consideration must be given here, because building uses and schedules can sometimes change much faster and easier than HVAC equipment.

Once the model is complete, a year long simulation identifies the hottest and coldest times of the year and tells the engineer what size of unit is required to cool and heat the building under those circumstances.  The engineer can then work with HVAC equipment suppliers to find a unit that fits the buildings needs.  Since the building will rarely encounter the peak loads, variable speed equipment has been designed which can effectively reduce the capacity of a unit so that it is “right-sized” more often then once or twice a year.  Once the unit is selected, design can continue with the layout of ductwork and selection of diffusers.  There are a many more considerations such as sound level for the remaining steps but that is a post for another day.

Forward Engineers routinely uses building modeling software in our designs and for our energy consulting services.  If you are seeking to work with an engineering firm that is client-centered and strives to provide services that are on time, on budget and exceed expectations, please contact us. We would love to work with you on your next project!

Forward Engineers is proud to announce that we have moved.  Our new location is in historic Downtown Rogers at the Vinson Building (1st and Elm).  We are coordinating with the Chamber of Commerce to host a ribbon cutting so stay tuned for details on when that will be.

Our contact information, including our mailing address will stay the same so no changes are needed if you send us anything.  I’m sure it will take us a few weeks to settle in, but please feel free to stop by and we’ll give you a tour.

Forward Engineers is a commercial building mechanical, electrical and plumbing (MEP) design firm.  We have over 30 years of combined experience designing retail, office, restaurant, multi-family, industrial, religious and institutional buildings.  We also provide energy efficiency consulting including energy audits for any budget, utility rebate applications, certification for the 179d tax deduction and more. If you are seeking to work with an engineering firm that is client-centered and strives to provide services that are on time, on budget and exceed expectations, please contact us. We would love to work with you on your next project!

My family and I recently visited the Fort Worth Zoo where we were sure to see one our favorite animals, the penguin.  While my children watched them dive and swim through the water, I was busy staring at the HVAC system keeping the penguins cool.

I’m no zoologist and I (unfortunately) haven’t had the opportunity to work on designing zoos, but a little reading let me know that an African Penguin requires en enclosure with an indoor air temperature anywhere between 37 to 72 °F.  Antarctic Penguins (of which there are several varieties) require even colder temperatures.  Humidity must also be kept low since penguins are highly susceptible to some types of infection like malaria and Aspergillus that thrive in warm humid environments.

As you can imagine, keeping an enclosure the right temperature and humidity for a penguin in an area of the country with routine temperatures above 100 °F can be tricky.  Beyond simply sizing the system large enough to meet the cooling demand, ventilation air must be carefully considered for the animals health.  Ventilation rates of up to 15 air changes per hour are recommended which can greatly increase the amount of A/C required.  For comparison, a restaurant may only require 8-10 air changes per hour.  To reduce the risk of infection, the air must be carefully filtered and the building pressurized to reduce unfiltered air from reaching the animals.  Since the air conditioner is critical to the animals health, back up systems should be included in the design so that the penguins won’t overheat if a system breaks down.

Penguin exhibits must also have water for the penguins to swim in.  Water temperatures must be kept between 32 and 85 °F for the African Penguin and just like a swimming pool it must be recirculated and filtered.  Special care must be taken when designing the drains to make sure a penguin can’t accidentally be sucked into the piping or hurt themselves on intake valves or skimmers.

Many different types of lighting have been used in penguin enclosures, but some studies show that varying the day length and light intensity to simulate a natural day can increase the health of the animals.  LED lighting can be used to great effect since it’s brightness and color can be changed relatively easily.

It’s not everyday that someone gets to design a specialty building like a penguin enclosure, but the principles of design and how engineers go about solving the problem are largely constants in the design world.  While we at Forward Engineers don’t design zoos, we do enjoy designing regular old buildings for our clients, and we love solving engineering challenges.  If you are seeking to work with an engineering firm that is client-centered and strives to provide services that are on time, on budget and exceed expectations, please contact us. We would love to work with you on your next project!