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ERV: Lower CO2 levels in a building & keep occupants alert & healthy


The most obvious reason to install an ERV is to recover energy when there is a fresh air requirement. When fresh air is brought into a building there is conditioned air exhausted back outside to equalize the pressure. The air leaving a building has energy in it - either warm energy in the winter or cool energy in the summer. An ERV allows you to capture 70% of the energy from the air leaving the building and put it back into the fresh air entering the building. This recapturing of energy means your rooftop unit does not have to work as hard and pays you back through lower monthly utility bills. The rooftop unit may also be sized smaller since it does not have to work as hard.

What are some other reasons to install an ERV? Workplace and school environments can have a high concentration of people and need plenty of fresh air. Adding fresh air lowers the CO2 levels in a building and helps to keep the occupants alert and healthy. ERV's also help to control odors since stale air is exhausted out of the building as fresh air is brought in. How about humidity? ERV's are effective at managing humidity by keeping moist air inside in the winter and outside in the summer.

ERV's can be critical for school jobs to comply with ASHRAE 90.1. Generally, you must bring in 15 CFM per student and must have at least 50% recovery on all systems with 5,000+ CFM and 70%+ outside air. The first check would be if 5,000+ CFM is being moved through the HVAC system. If it is, then the next step would be to divide your total CFM by the outside air to find out if you are bringing in at least 70% outside air.

For example, a local school has an 8,000 CFM HVAC system and 400 students. Here are the steps to determine if 50% recovery is required:

  • The HVAC system delivers 8,000 CFM so it is over the 5,000 CFM minimum.

  • 400 students require 6,000 CFM of fresh air (400 x 15 CFM = 6,000 CFM)

  • 6,000 CFM / 8,000 CFM = 75%
In this case the school's HVAC system must bring in over 70% of outside air so some type of recovery is required. ERV's from Ruskin and Ruskin Rooftop Systems achieve well over the 50% recovery required
by ASHRAE 90.1. Jim Connell, Vice President Sales at Airxchange, says, “Adding Energy Recovery Ventilators to school projects has nearly a 100% hit rate due to the energy efficiencies and cost savings gained.”

See the full Engineering Report

Energy Recovery Ventilators (ERV)

Ruskin's Energy Recovery Ventilators (ERVs) recapture conditioned air to reduce energy usage in HVAC systems. MiniVentilator (MV) units provide energy recovery for indoor applications ranging from 250 - 1000 CFM. Low profile cabinet is ideal for schools and small office. The ENERVENT and ENERVENT+ units operate in a CFM range of 600 - 12000. Additionally, ENERVENT+ units have auxiliary heat and cool options including Indirect Gas-Fired post heat. ENERVENT standalone units can be indoor or outdoor and either ducted to the AHU or directly into the HVAC system.

Indoor ERV Models

Outdoor ERV Models

ERV Models with Heating and Cooling options

EnERVent+ Series

Regardless of building type or rating system, today’s building must be as energy efficient as possible. The design of the HVAC system is critical to the success of the building’s energy performance. Proper ventilation for occupant health and productivity must also be addressed. The quality of the indoor environment cannot be sacrificed for the sake of energy efficiency.

EnERVent+ by Ruskin is your solution. Increased ventilation rates in combination with energy recovery products not only improve the indoor air quality but also reduce the cost associated with conditioning these larger amounts of outdoor air.

Benefits of Energy Recovery
  • Energy savings provide exceptional payback
  • LEED-EB and LEED-NC Credits
  • ASHRAE Compliance and IAQ
Download EnERVent+ Product Brochure

EnERVent Series

Energy Recovery Ventilators (ERV) are used to recover exhaust air energy and reintroduce it into the conditioned space. The recovery wheel provides sensible and latent energy exchange between the entering and exhaust air streams of a building. This allows a substantial amount of the energy which is normally lost in the exhaust air stream to be returned into the entering air. Ideal applications are areas that have cold or hot temperatures with high occupancy loads or high ventilation requirements. Areas that have high humidity or very low humidity (recover exhaust air humidity from buildings that have humidifiers) are good applications. ERV’s also reduce the design loads due to outside air, which can mean downsizing the air conditioning equipment. Application software is available to calculate the load reductions and provide the energy and dollar savings for all areas of the United States and Canada.

Principle of Operation
The ERV enthalpy wheel contains parallel layers of a polymeric material that are impregnated with silica gel (desiccant). The wheel is located in the entering (intake) air and exhaust air streams of the ventilation equipment. As the wheel rotates through each air stream, the wheel surface captures sensible and latent energy. In the heating mode, the wheel rotates to provide a constant transfer of heat from the exhaust air stream to the colder intake air stream. During the cooling season, the process is reversed. For applications that do not need to recover energy during mild outside weather conditions, an option is provided to stop the wheel from rotating, thereby providing cooling with energy recovery

Download EnERVent Product Brochure

About Ruskin

"Since 1958, Ruskin is the name in air management solutions that engineers, architects and contractors rely on to make buildings safer, more energy efficient and comfortable. Our mission is to make everyone comfortable. From the owners, to the designers, to the installers, to the occupants, Ruskin and our industry partners strive to make your well-being our top priority. We offer the most complete line of air control and architectural products and support them with our reputation for quality design and precision manufacturing. With Ruskin, every product is backed by cutting-edge technology, rigorous testing, on-time delivery and technical support".

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