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Ventilation and VRF for Multi-functional Campus Buildings

Set to officially open in July 2018, George Mason University’s Global Center is the home of INTO Mason, a language and academic preparation program designed for international students. Originally a hotel, the seven-story, 102,000-square-foot space houses 270 students year round, hosts a full-service dining facility as well as classrooms and administrative offices. Now that the former hotel rooms have turned into dorm rooms, the school is putting the final touches on the academic spaces. As with any educational space, ensuring the proper amount of outside air and student comfort was critical to the building’s renovation.

GMU selected Mitsubishi Electric’s CITY MULTI® Variable Refrigerant Flow (VRF) technology and PremiSys Fusion DOAS for its cooling, heating and ventilation needs. We spoke with the project’s contractor and HVAC engineer who explained why these systems were the right choice.


“We knew that zoning was going to be optimal for a building like this with both offices and classrooms. Mitsubishi Electric is also the only brand that could easily accommodate future HVAC additions. With their two-pipe system, it’s easy to attach another unit to the branch controller box in case the school wants to expand in the future. Other brands using three pipes don’t offer that. In addition, for this project, the previous hotel was LEED certified, and using Mitsubishi equipment made it easy to maintain that certification.”

Why PremiSys Fusion?

“The building originally had a dedicated outside air system (DOAS) but with VRF’s efficiencies, it ended up being oversized.The PremiSys Fusion unit was also ideal for meeting the Virginia Energy Code for educational facilities. We used one PremiSys Fusion DOAS unit for the administrative spaces and will use another for the classrooms. Using this unit actually reduced the amount of ductwork needed.”


“The school already had a lot of Mitsubishi Electric equipment in other buildings so it makes sense it was specified here as well. VRF is very quiet which is why it works so well in the classroom especially compared to VAV boxes or fan coil units…the noise levels are low. Aireco was especially helpful in getting us started with the CITY MULTI equipment for this job as well. They’re cost-effective and friendly.”

Why PremiSys Fusion?

“There are two reasons why the PremiSys DOAS works well for this kind of project. It has the same controls platform as the VRF system and can be tied to the front-end interface unlike if we were to use a different brand’s DOAS system. Secondly, these units are extremely energy efficient. With PremiSys, there’s an energy recovery wheel. Instead of using 100 percent outside air, the system brings in exhaust air and mixes it with outside air which is then used by the outdoor unit. This allows for efficiency and humidity control.”

Benefits of Mitsubishi Electric Two-Pipe VRF

Here at Advanced Products Group (APG) we’re committed to providing our customers the top HVAC technologies and systems. That’s why we offer Mitsubishi Electric CITY MULTI® VRF technology. Curious about VRF? Review our listing of VRF’s main benefits below:

Cost Savings:

Mitsubishi Electric offers simultaneous heating and cooling VRF in a two-pipe system while most of the industry still requires three pipes. The branch controller (BC) configurations eliminate the need for individual “selector” boxes in each zone, reducing costly and unnecessary proprietary fittings as well as the additional piping and electrical connections that are inherent in a three-pipe system. In addition, utilizing pre-insulated soft copper tubing between the branch controllers and the evaporators reduces labor costs and eliminates possible leak points associated with the use of standard hard copper.

Precise Control:

Two-pipe architecture allows indoor units to change temperature quickly from cooling to heating, or heating to cooling. The cooler/hotter refrigerant from one indoor unit moves to the branch controller and gets redistributed right there to another indoor unit. Since a three-pipe system’s refrigerant has to be moved farther to undergo the same redistribution process, the system responds more slowly, loses energy and costs more money to operate.

Energy Efficiency:

Energy efficiency is key in today’s marketplace. Mitsubishi Electric’s INVERTER-driven compressor technology uses the absolute minimum energy necessary to maintain personalized comfort levels while adjusting to part-load conditions, which occur most frequently. VRF systems consistently perform at 25 percent higher efficiency than conventional HVAC systems and help eliminate hot and cold spots.

Superior Technical Support:

Mitsubishi Electric has an unmatched technical support infrastructure across the U.S. As a part of its distributor network, APG is proud to offer comprehensive training on CITY MULTI VRF technology. Instructors provide lectures and hands-on training and are an open resource for students both in the classroom and out in the field.

Ease of Serviceability and Maintenance:

With the use of refrigeration ball valves on each circuit, CITY MULTI VRF systems have unmatched maintenance flexibility. An individual zone can be shut down, serviced and even relocated without affecting the functionality of the rest of the system. Through comprehensive controls – such as the CITY MULTI® Controls Network or Diamond Controls™ Solutions – technicians have remote access to the system and maintenance data which can be monitored and adjusted without the need for a third-party controls system. These features bring an owner piece of mind and build value for a servicing technician in meeting the needs of their customer.

Mitsubishi Electric VRF Provides Renovated Hotel Efficiencies and Flexibility

The Virginian Hotel will soon be the gem of downtown Lynchburg, Virginia. Originally built in 1913, the historic building has gone through many changes over the years. Formerly known as “The Grand Hotel of Downtown Lynchburg,” the property has also functioned as student residences for Liberty University and low-income housing. When the property went up for sale in 2014, George Stanley and his team at Cityscape, LLC decided to return the building back to its hotel roots. Once complete, this 114,000-square-foot hotel will feature 115 guest rooms, 10,000 square feet of conference and banquet space, a ballroom and several dining options including a rooftop restaurant, coffee shop and steakhouse.

With multiple functions for the space, a flexible HVAC system was key. The project team’s choice: Mitsubishi Electric Variable Refrigerant Flow (VRF) technology. Below we talk with George Stanley, owner, The Virginian Hotel, and Melinda Ruble, mechanical engineer, MDR Engineering, about the development and why Mitsubishi Electric VRF was the right selection for this project.

What is the concept of this hotel?
When we first explored the building, we knew it had potential. This hotel blends the historic with modern amenities. It’s also part of Hilton’s Curio Collection, which is their soft brand. They handle operations but we are our own unique brand.

Why VRF?
VRF is an extremely efficient system in how the units play off one another. One is heating and one is cooling – there’s an efficiency there. You don’t pay for the connection twice. We also didn’t have a lot of ceiling space for piping. Mitsubishi has a two-pipe system versus other market competitors that use three pipes. This feature was critical to the job. Having never used Mitsubishi Electric previously, I would absolutely use them again.

Did you receive any technical assistance regarding Mitsubishi Electric products?
Bill Warner at Aireco was instrumental in the selection and is as solid as they come. He was there to explain any questions we had and has given us full confidence in the system.

Apparently, the project team was torn between a traditional chiller/boiler four-pipe system and VRF before they made their final HVAC decision. What led to VRF?

There were a lot of historical constraints with this job – one of which involved maintaining ceiling heights to preserve the historic nature of the building. To have chilled water and heated water running through piping on a building this size was really going to be difficult. In my opinion, this naturally needed to be a Mitsubishi Electric VRF system.

Why is VRF technology an efficient choice for hospitality settings?

In a hotel, there are large areas that potentially are going to be unused at any time. It is unlikely to have all guest rooms booked 100 percent of the time. With VRF, you get the energy sharing – if you have one space that requires cooling and heating, you can have simultaneous conditioning that allows you to conserve energy and save money. You also get the zoning. As a crowd moves within a space, the system picks that up and allows the building to meet the conditioning demands.
Project Team

The Virginian Hotel is set to open mid-May.

Watch the project profile video.

Aireco Wins Big at the 2018 Mitsubishi Electric Diamond Leadership Conference!

We are pleased to announce Aireco Supply, Inc. won the South Business Unit Residential and Commercial Diamond Partner of the Year at the Diamond Leadership Conference held March 2 – 5, at Atlantis, Paradise Island, Bahamas. This award reflects our achievements in 2017 which include: opening the new Newport News Training Center, conducting three Mitsubishi Electric Dealer meetings and holding over 3,000 hours of systems training. We are honored to receive this award and will continue reaching new heights to provide our customers with quality products and services!

Mitsubishi Electric’s Water-Source VRFHelps Solve Restaurant Group’s Overheating Issues

Farmers Restaurant Group, Kensington, Maryland, is a local restaurant developer that specializes in farm-to-table cuisine and highlighting homegrown flavor. They own and manage the popular restaurant Founding Farmers as well as its sister establishments Farmers Fishers Bakers and Farmers & Distillers. After experiencing overheating issues in two of their locations last year, Farmers Restaurant Group worked with APG and MECCO Inc., Jessup, Maryland – the HVAC seller and installer – to supplement their traditional conditioning systems with Mitsubishi Electric Cooling & Heating’s CITY MULTI® VRF. See our breakdown below on each restaurant with insight from J.J. Sabins, facility manager, Farmers Restaurant Group and Rusty Mack, project manager, MECCO Inc.

Facility Manager’s Perspective: “The bar was too hot,” explained Sabins. “Especially in the summertime, we weren’t able to effectively cool down the restaurant. When we engineered the restaurant’s capacity, we had one ton of cooling per 100 square feet. We ended up being a little short in the calculation. With expensive, hand-made wooden ceilings, we could not use a ducted system.”

Solution: Mitsubishi Electric’s CITY MULTI Water-Source VRF

Contractor’s Perspective: “Several of the HVAC units being used were inherited,” noted Mack. “On the weekends as the bar got really busy, the systems couldn’t keep up. They needed supplemental cooling. We put in several evaporators with a water-cooled condensing unit in the equipment room. With no ductwork required, it was a perfect fit. The ceiling cassettes were installed into the high exposed ceilings and painted black.”

Equipment Used:

  • (1) Y-Series Water-source Unit
  • (2) Branch Joints
  • (1) Branch Header
  • (5) PLFY Ceiling Cassettes

(1) Wired MA Remote Controller

Facility Manager’s Perspective: “This is our highest volume restaurant in the group,” noted Sabins. “The kitchen, which is a fraction of the size of our other locations, was only made with 14-tons of cooling and it’s a busy space. With a kitchen that small, it’s full. You’ve got your kitchen exhaust ducts, dishwasher exhaust ducts, electrical…the ceilings are full with no room for ductwork.”

Solution: Mitsubishi Electric’s CITY MULTI Water-Source VRF

Contractor’s Perspective: “Their traditional HVAC system was no longer running up to 100 percent capacity,” said Mack. “On Friday and Saturday nights, the system couldn’t keep up. The nice thing about Mitsubishi Electric’s VRF system is that it ramps up and down based on the load. With more guests, the system picks up and then with less people, it automatically adjusts the comfort level. We were able to add another 14 tons of cooling.”

Equipment Used:

  • (1) Y-Series Water-source Unit
  • (4) Branch Joints
  • (5) PLFY Ceiling Cassettes

(1) Smart ME Remote Controller