FAQs - Energy Recovery Ventilators
- Can the aluminum plate used in Model PVe develop frost?
- Can we incorporate supplemental heating and/or cooling components into an energy recovery unit?
- Do Greenheck packaged units have stand alone unit controls?
- Does Greenheck provide vibration isolated roof curbs?
- Does the energy recovery wheel act like a filter?
- How does the effectiveness of an energy recovery wheel compare to an aluminum heat exchanger or energy core?
- Is it difficult to change an ERV wired for 460/60/3 to 208/60/3?
- Is the energy recovery wheel AHRI certified?
- What certifications do energy recovery units carry?
- What is the cross leakage rate for an energy recovery wheel?
- What is the energy recovery wheel made of?
- What is the expected life span of an energy recovery wheel?
- What is the highest turndown ratio available on your indirect gas fired packaged RV/E units?
- What is the recommended cleaning procedure for an aluminum plate heat exchanger?
- What is the recommended cleaning procedure for an energy recovery wheel?
- What type of applications are recommended for a plate-type heat recovery device?
- What type of applications use energy recovery?
- What type of benefit do the low sound condensing fans provide?
- What type of salt spray rating does the Hi-Pro Poly coating have?
Q: Can the aluminum plate used in Model PVe develop frost?A: Yes, in colder climates that have higher humidity levels, frost may form on the plate exchanger. To protect against the formation of frost, there are two different frost control methods that are offered.
Timed exhaust is an economical option which allows the supply blower to cycle on and off based on a timer while the exhaust blower continues to blow, melting any frost that has formed on the plate.
Plate heat exchanger bypass is another option fro applications that require a constant supply of outdoor air. If the exhaust air leaving the heat exchanger drops below the adjustable set point, the face and bypass dampers will allow air to bypass the heat exchanger. This will allow warm exhaust air to melt any frost the has formed on the plate.
Q: Can we incorporate supplemental heating and/or cooling components into an energy recovery unit?A: Greenheck offers several Energy Recovery units which incorporate heating and cooling components. Model RVE, ERCH, ERT, and the APEX have several heating and cooling configurations available. Please contact your local Greenheck Representative for more information.
Q: Do Greenheck packaged units have stand alone unit controls?A: Yes, Greenheck packaged units are available with a stand alone microprocessor. The microprocessor will be preprogrammed from the factory and offer user friendly navigation. All sequences are designed and tested in house with factory support available.
Q: Does Greenheck provide vibration isolated roof curbs?A: Greenheck currently does not provide any type of vibration isolation or seismic rated roof curbs.
Q: Does the energy recovery wheel act like a filter?A: No, the Energy Recovery wheel does not act like a filter. This component is designed to produce laminar/smooth airflow which allows small particles to pass through the wheel. Larger particles may impinge on the wheel surface but can be blown off as the wheel rotates to the counter-flowing air stream.
Q: How does the effectiveness of an energy recovery wheel compare to an aluminum heat exchanger or energy core?A: Aluminum plate heat exchangers transfer sensible energy (heat) only and have a total effectiveness of 30%. Hydroscopic energy cores will transfer sensible and latent energy and have a total effectiveness of 50-60%. Energy recovery wheels manufactured out of a polymer material with a silica gel desiccant will transfer sensible and latent energy and have a total effectiveness of 70-80%.
Q: Is it difficult to change an ERV wired for 460/60/3 to 208/60/3?A: Voltage changes for ERVs can be very time consuming and expensive. In order to change the voltage, several components must be replaced including fan motors, fan drives, motor starters, contactors, and overloads. In some cases, disconnect sizes may also change. Wiring will need to be rerun to handle the higher amp drawings at the lower voltage.
Q: Is the energy recovery wheel AHRI certified?A: Yes, the energy recovery wheel is certified per AHRI 1060-2000. Component and packages certified to this standard are shown in the AHRI Certified Product Directory for Air-to-Air Energy Recovery Ventilation Equipment. AHRI certified ratings include information such as energy transfer effectiveness, pressure drop, and cross leakage (EATR & OACF).
Q: What certifications do energy recovery units carry?A: Greenheck energy recovery products carry an ETL listing for electrical safety, AHRI certification for energy recovery components, and an AMCA seal for air performance of the fans. These certifications are important to have on the unit to reassure engineers or owners that the performance published by a manufacturer is the performance that they will actually get.
Q: What is the cross leakage rate for an energy recovery wheel?A: Typical EATR (exhaust air transfer ratio) will be anywhere from 3-5%. AHRI certificates will list this information and can be found on the AHRI Certified Product Directory or printed within your CAPS submittal. Per ASHRAE 62.1, class 3 air (ex. Restroom) will allow an EATR of up to 5% which allows for the usage of an energy recovery wheel.
Q: What is the energy recovery wheel made of?A: Greenheck Energy Recovery products use an "enthalpy" wheel composed of a lightweight polymer embedded with a silica gel desiccant. The polymer media transfers sensible energy (heat) while the silica gel desiccant transfers the latent energy (moisture).
Q: What is the expected life span of an energy recovery wheel?A: Energy recovery wheels used in Greenheck products have a typical life-span of 15-20 years based on the recommended cleaning and maintenance procedure. In that time, performance of these wheels has been excellent with less than a 5% reduction in latent effectiveness. In addition to the longevity and reliability, Greenheck offers a standard five year warranty on this component.
Q: What is the highest turndown ratio available on your indirect gas fired packaged RV/E units?A: The highest turndown ratio for an indirect gas fired furnace in an RV/E unit is 16:1. This seamless turndown option allows for precise temperature control and a decreased firing rate resulting in less furnace cycling on part load days. The furnaces can be programmed to maintain a discharge or room temperature controlled via the unit microprocessor or a building management system (BMS).
Q: What is the recommended cleaning procedure for an aluminum plate heat exchanger?A: Aluminum plate heat exchangers should be cleaned by either vacuuming off the surface or sprayed with water/detergent. It is recommended to use hot water (180°F) or detergents that will not damage the aluminum, sprayed at a pressure of 22-55 psi. Please refer to the product's IOM for more information.
Q: What is the recommended cleaning procedure for an energy recovery wheel?A: Greenheck recommends that the energy recovery wheel and/or wheel segments be cleaned every 2 to 3 years depending on the application. For applications that exhaust smoke, oil particles, etc., it is recommended that they are cleaned every 2 to 3 months. Wheels should be cleaned in an alkaline detergent solution and rinsed with low pressure water. All wheels and segments should be completely dry before being installed back into the unit.
Q: What type of applications are recommended for a plate-type heat recovery device?A:
In regions where latent loads are not a concern, the plate-type heat recovery device can be an economical and effective way to transfer dry energy. The plate-type heat recovery device can also be used for low leakage applications as it has an EATR of 0-1%.
Q: What type of applications use energy recovery?A: Energy recovery can be used in numerous commercial or institutional comfort ventilation applications such as schools, dormitories, offices, hotels/motels, nail salons, or restaurants. The southeastern, Midwestern, and eastern portions of the United States have excellent climates for energy recovery where there are significant cost/energy savings.
Q: What type of benefit do the low sound condensing fans provide?A: Low sound condensing fans offered on models RV and RVE offer several benefits. These condensing fans offer a sound power reduction on average of 5-8 dB and a perceived sound level reduction of up to 50%. The assembly features a serrated fan blade design for increased fan efficiency and an optional EC motor for increased system efficiency.
Q: What type of salt spray rating does the Hi-Pro Poly coating have?A: Greenheck's Hi-Pro Poly coating has a salt spray rating per ASTM B117 of 5000 hours. The Hi-Pro Polyester coating shoud be utilized in corrosive environments such as that seen with coastal applications.