In the HVACR world, it is not impossible that the designers of a walk-in cooler/freezer to mistakenly chose the wrong FPI (fins per inch) selection for the application you are servicing. Here is a table to reference when you are looking at possible causes of an iced-up coil. With fin spacing too close, frost can easily bridge the gap and quickly reduce air flow through the evaporator.
The proper selection of fins per inch plays a role in maintaining proper humidity levels in the conditioned space as well. The bottom line is this: don’t always assume that the application engineer can’t make a mistake in the selection process. Always look at this factor when troubleshooting your HVACR evaporator problems.
The final factor in evaluating the air distribution in a space is the comfort of the occupants. In general, a person is thermally comfortable when body heat loss equals body heat production. What most people call a “draft” is simply a slight movement of air that results in a local feeling of “coolness.” It has been determined that a velocity change of 15 ft/min has about the same effect on comfort as a 1°F of temperature change. KEEP READING BELOW…..
A typical room air distribution system with local air velocities of less than 40 to 80 ft/min will satisfy 80% of occupants. Localized air temperatures should be less than 2°F below the general room temperature. The temperature near the floor should be less than 4°F below that at about shoulder height. For heating, local air velocities generally are below 40 ft/min. For cooling, local air velocities should be between 40 and 80 ft/min.
Rolling Meadows, Ill. (Dec. 14, 2017) – RSES is pleased to announce the addition of four additional HVACR training books to its online store. All four titles are published by ESCO Group and add to the ever-expanding library of materials RSES offers to help industry professionals excel at their jobs.
Sample sections of each manual are available in the Table of Contents tab in the description section at the online store. For more information or to order these items visit www.rses.org/store or call 800-297-5660. Please note, RSES Members will need to login to the website first in order to receive the appropriate member discount.
FOR ALL YOU REFRIGERATION GUYS OUT THERE…..FIND OUT MORE HERE: https://goo.gl/EK8fSA
There is a lot going on in the world of Refrigeration. Electronics, alternative refrigerants and new ways to service equipment. One way to keep ahead of these changes and grow your business is to sign up for Refrigeration Contractor Weekly.
BATAVIA, Ill., Dec. 11, 2017 /PRNewswire/ — ALDI has received the 2016 – 2017 “Best of the Best” award from the Environmental Protection Agency’s GreenChill Partnership for its use of cutting-edge, environmentally sustainable refrigeration systems in 34 of its stores. READ MORE
Special considerations must be taken when installing condensers in cooler climates. During the colder weather, a winterizing valve should be utilized to maintain head pressure. This valve is actuated by a pressure difference between its inlet and outlet. The figure shows a “Winterstat” brand. Other valves may be used such as a “Headmaster” valve. If system pump-down is a desired feature, the receiver must hold the normal refrigerant charge plus the condenser charge with the bypass valve operating ̶ that is, partially open or intermittently opening and closing.EXCERPT FROM “TOOLS, CONTROLS AND TROUBLESHOOTING“, available from the ONLINE STORE at RSES.ORG.