Story at a glance:
- LG’s Split Rooftop and Split Compact Dedicated Outdoor Air System, or DOAS, are two of the most efficient units on the market today.
- DOAS units are used with additional HVAC equipment to bring fresh outdoor air inside as a way to greatly improve indoor air quality.
Today building owners are searching for ways to keep occupants comfortable and healthy indoors more than ever, as businesses are reopening and workers all over the country return to the office. It has become crucial for new technology in HVAC systems to achieve quality indoor air in a way that is cost effective and sustainable for the environment. LG Electronics Air Conditioning Technologies Division, which has been creating leading energy-efficient products on the market for decades, is contributing in major ways.
LG recently launched the Split Rooftop and Split Compact Dedicated Outdoor Air System, or DOAS—two of the more effective and efficient units available on the market today. This enables building owners and facility managers to efficiently condition outside air for improved indoor air quality and comfort, without sacrificing flexibility, reliability, or ease of integration.
DOAS units are used with additional HVAC equipment to bring fresh outdoor air inside as a way to greatly improve indoor air quality. LG DOAS is designed to provide better humidity control and improve indoor air quality by circulating outdoor air inside. It collects and treats the outdoor air. Outside air is cooled, warmed, or dehumidified to create a neutral temperature and is then circulated indoors. LG’s DOAS units have unique factory-installed features like energy recovery wheels, which passively cool and reheat air by transferring energy while decreasing the need for fossil fuel resources.
These dedicated outdoor air systems units are now being installed in new construction and retrofitting projects across the U.S. to improve indoor air quality. We recently talked to Ed Ferrier, senior manager of engineering for LG Air Conditioning Technologies USA, to learn more.
What are LG’s new Dedicated Outdoor Air Systems?
Front top view. Photo courtesy of LG Electronics
We just launched a Split Rooftop DOAS and a Split Compact DOAS unit. The split rooftop’s size range is 2,000 to 3,000 cubic feet per meter (CFM), and the indoor compact comes in two models where the size range is 1,000 to 2,000 CFM. We rate these systems based on CFM as the airflow rate, because it is critical with any dedicated outdoor air system to know how much air you can bring in.
The split compact and the rooftop dedicated outdoor air systems have unique features that other products on the market don’t really have. With built-in heat recovery units, both the Split Rooftop DOAS and Indoor Split DOAS are easier to install, requiring less labor, and are ideal for applications where roof limitations prevent the use of a packaged rooftop DOAS. The new DOAS feature longer pipe lengths that allow for remote connection to LG VRF Multi V units as a solution for onsite space restrictions, providing more design flexibility.
LG’s Split DOAS includes a web user interface for remote accessibility along with the option for VRF and DOAS interlocked operation via LG communication protocol. Such features enable seamless integration without the need for third-party platforms.
How do DOAS work, and how do they integrate with other equipment?
Photo courtesy of LG Electronics
Both of these new LG Split DOAS units include factory-installed hot gas reheat coils, a heat recovery box, and built-in controls, which measure incoming outdoor air temperatures and humidity levels. Based on these readings, the controller utilizes pre-programmed internal logic to determine the operating mode the system should be in to ensure comfortable neutral air temperature for the occupants of the building. The operating modes are cooling, heating, or dehumidification. When we say room neutral, that is generally 70 to 75 degrees Fahrenheit. It’s not too hot and it’s not too cold—just a neutral temperature most people are comfortable with.
Our DOAS units are fully integrated with LG controls to provide a whole building with easy-to-use HVAC control solutions. Like with the LG AC Smart Gateway, the building user can quickly access both the DOAS system and the VRF (Variable Refrigerant Flow) system. They can turn them on or off at a set point with a touch screen controller.
The Split Rooftop DOAS also combines with a unique secondary energy recovery coil. That coil is on the exhaust side of the energy recovery wheel. Its sole purpose is to extract energy from the exhaust air before it is sent outdoors and by doing so the recovery coil contributes to the high energy efficiency ratings of the DOAS.
How can improving IAQ make a space more comfortable?
Bringing in the proper amount of outdoor air prescribed by your local code is necessary to contribute to healthy and comfortable environments for building occupants. In light of the COVID-19 outbreak and subsequent lockdowns, resulting in more time spent indoors, the importance of indoor air quality is an important and relevant topic.
How has the need for solutions to improve IAQ changed over time?
Before the Covid-19 pandemic, most customers were looking for the bare minimum filtration. The minimum code requirement is the MERV (minimum efficiency reporting value) 8 filter rating. With the emergence of Covid-19, more attention has been focused on improving IAQ, and LG has found that clients are switching to MERV 13 and MERV 14 filters because they are more efficient at removing particulates. We are also seeing more inquiries for UV lights and bipolar ionizers, and some of our DOAS units have those options.
There is definitely a drive to create better DOAS on the market. Increasing ventilation with outdoor air and air filtration are important components of a larger air quality strategy. The reality is, to bring in outside air you need a fully designed dedicated outdoor air system.
What makes LG’s DOAS a sustainable solution?
LG has always focused on being the most energy-efficient we can be. We offer unique features and solutions in both comfort cooling VRF systems and DOAS units.
We are noticing a trend in certain areas of the country now where gas heat can no longer be used in new construction—either because their infrastructure is overtaxed or they’re trying to reduce fossil fuel consumption for less carbon emission. Those places have really embraced the heat pump heating technology.
Both of our new Split DOAS systems connect to our Multi VTM 5 VRF units, which provide heat pump heat. In these applications there’s no need to bring in gas, and heat pump heating has been proven to be much more energy-efficient than just electric heat. Electric heat has a COP (coefficient of performance) rating of 1.0 while our heating systems achieve a higher COP, which means a more energy-efficient rating of 3 to 4 depending on the size because we are using inverter compressions and heat pump heating.
What type of application is a DOAS best suited for?
Photo courtesy of LG Electronics
DOAS units complement the VRF systems, so any location where you have VRF we typically recommend you have a separate DOAS to treat the air.
Some of our key applications for DOAS have been hotels, schools (kindergarten through 12th grade and higher education), condo buildings, assisted living facilities, office buildings, and more.
The new LG Split DOAS units are a good application for retrofitting existing buildings. Sometimes, when there is limited ceiling space or only so much room where pipe and ductwork can run, Split DOAS can help in that situation. We can also reduce the amount of structural steel needed for supporting rooftop units with these.
Can you share some examples of DOAS in action?
We have an assisted living facility in Atlanta that will be installing three of the split rooftop units toward the end of the year. They are going to complement an LG VRF system. It’s an interesting project in that the owner was able to secure a large utility rebate from the local utility company because they proved how much more energy-efficient these systems were than a conventional system.
How is LG leading the way in this industry?
We are leading the way in energy-efficient solutions by focusing on providing a total building HVAC solution that includes the VRF and LG DOAS to meet ventilation needs by bringing in outside air and providing cooling systems as well.
We can provide all of those, so it makes it easier on the owner, as they have one place to contact for service or to make a purchase. LG is leading the way in providing a package-integrated solution. We are also leading with our people and our tech support. We strive to keep customers happy.
Unique features make LG’s Split DOAS leaders in the industry and the more sustainable models on the market. The Split DOAS has a factory-installed heat recovery box, which can be installed with up to four of the units connected to just one outdoor condensing unit. No one else on the market does that right now. The Split Rooftop DOAS also has an energy recovery wheel with a factory-installed recovery box and the secondary energy recovery coil outside the wheel. There isn’t any other equipment like this available on the market today.
