New Refrigeration on Used Walk-ins – Is it EISA compliant?

The Department of Energy (DOE) has written their interpretation on compliant refrigeration vs. non-compliant refrigeration on walk-in coolers and freezers. Below, DOE explains that any component added to a previously installed walk-in cooler or freezer and manufactured after January 1, 2009, must meet EISA guidelines. This is a draft document and comments and suggestions must be submitted to the Department of Energy prior to February 20, 2012.

The Interpretation from the Department of Energy (DOE)

This is a draft document and does not represent a definitive view of the agency on the questions addressed.

This and other guidance documents are accessible on the U.S. Department of Energy, Energy Efficiency & Renewable Energy web site at: http://www1.eere.energy.gov/guidance/default.aspx?pid=2&spid=1.

Guidance Type: Conservation Standards, Enforcement
Category: Commercial Equipment
Product: Walk-in Cooler and Walk-in Freezers
Guidance Version: DRAFT
Issued: January 20, 2012
Comment Period Closes: February 20, 2012

Q: What are the relevant dates for compliance with the prescriptive requirements for walk-in coolers and walk-in freezers? For example: If a newly manufactured component of a walk-in cooler or walk-in freezer is installed in a walk-in box manufactured prior to January 1, 2009, does it have to comply with the prescriptive requirements of 10 C.F.R. § 431.306?

A: The following is a draft U.S. Department of Energy (DOE) guidance document regarding commercial walk-in coolers and walk-in freezers. This draft guidance document represents the Department’s interpretation of its existing regulations and is exempt from the notice and comment requirements of the Administrative Procedure Act. See 5 U.S.C. § 553(b)(A). Therefore, the Department is accepting comments and suggestions from the public until February 20, 2012. Comments and suggestions should be provided in WordPerfect, Microsoft Word, PDF, or text file format by sending an email to WICFEISA2007Guidance-2012-0001{at}ee.doe.gov. Please also include the docket number EERE-2012-BT-STD0001.

At the end of the comment period, this draft guidance document may be adopted, revised or withdrawn. Read the rest of this entry »

Troubleshooting Defrost Problems

When troubleshooting walk-in freezers, technicians often find a frozen evaporator coil. Although there are several possible causes, one common cause involves the defrost system. For some reason, the system is not properly defrosting the evaporator’s coil on a regular basis. In order to effectively troubleshoot this problem, a technician must understand the design and operation of the defrost systems typically used.

One popular method of defrosting walk-in freezers is the electric defrost system. This is comprised of several components, including a defrost timer, resistive heater(s), defrost termination switch, fan cycling control, and drain line heater. An electric resistance heater is placed on the outer surface of the evaporator’s coils. The energized heater supplies enough heat to completely defrost the coils.

The resistive heaters used on a typical electric defrost system are sized to provide sufficient heat to effectively defrost the coil’s surface. Their capacity is normally rated in watts per foot. They are shaped to fit snugly onto the coil surface, creating efficient heat transfer during defrosts.

Most heaters are manufactured for a specific coil, and when replacing these heaters it is best to obtain the OEM replacement. Universal defrost heaters are available, but matching their wattage and shape may be difficult.

A defrost timer controls the entire defrost operation. It initiates the defrost cycle, controls the operation of the compressor and defrost heaters, and is part of the defrost termination. Defrost timers can be adjusted to initiate defrost from just once a day to several times a day.

The actual number of defrosts per day depends upon the location of the walk-in. Walk-in freezers are usually designed to defrost once or twice a day. The more humid and warm a location, the more defrosts will be needed. If a system needs to be defrosted more frequently, add only one additional defrost period at a time and monitor the results. Adding too many defrost periods will not be beneficial to the system or the customer.

In a common wiring diagram for a time-initiated, temperature-terminated electric defrost system the time motor (TM) is energized continuously. Normally closed contacts 2-4 of the defrost timer are wired in series with the compressor and the evaporator fan motor (EFM). Normally open contacts 1-3 are wired in series with the electric defrost heaters and the timer release solenoid (TRS).

The timer motor controls the operation of contacts 2-4 and 1-3. They work opposite each other. When contacts 2-4 are closed, 1-3 are opened. When contacts 2-4 are opened, 1-3 are closed. When the timer motor initiates a defrost, contacts 2-4 will open and 1-3 will close. This stops the compressor and the evaporator fan motor, and energizes the defrost heaters. Read the rest of this entry »

Refrigeration Guidelines for Specific Applications

This article is courtesy of Austin Industrial Refrigeration.

Flowers do best with High Humidity and Low Velocity refrigeration

Aside from the box temperature, other considerations that are particular to medium temperature applications (walk-in coolers & refrigerators) are the air velocity and humidity of the refrigerated space. Below freezing, humidity is inherent (the moisture is mostly frozen out of the air), so low temp applications are easier to spec than medium temp.

The following are common design parameters and examples of their application:

• 35 degrees F / 90%+ relative humidity (low velocity coils) – high humidity – Used for: sensitive materials, floral – roses
• 35 degrees F / 85% – 90% relative humidity – general purpose – Used for: foodservice, fresh meats, packaged goods not sensitive to humidity, short-term mixed produce, thawing, and dry goods unaffected by humidity
• 35 degrees F / 60% – 75% humidity – low humidity – Used for: retail, beer and beverage coolers, packaged items, materials sensitive to humidity
•  45 degrees F / 55% – 70% humidity – low humidity – Used for: aging red wine
• 45 degrees F / 90%+ humidity (low velocity coils) -high humidity – Used for: sensitive materials, floral – general
• 55 degrees F / 55% – 70% humidity – low humidity – Used for: processing rooms occupied by personnel
• 55 degrees F / 60% – 75% humidity (low velocity coils) – low humidity – Used for: produce Read the rest of this entry »

Refrigeration History: Then and Now

–Philip J Reed, on behalf of Redstone College

Chances are you’ve recently pulled a soda or cold drink of water out of the fridge without giving it much thought. Maybe you dodged summer heat by heading to your air conditioned home. These refrigeration luxuries have done a great deal to change modern living, but avoiding a sweltering day or keeping food cool for consumption later hasn’t always been so easy.

Early Days

Jacob Perkins Refrigerator Photo: Xtimeline

Jacob Perkins created the “first practical refrigerating machine” in 1834, according to the Environmental Protection Agency, and the unit used ether in a vapor-compression cycle. A refrigeration machine in 1850 relied on water and sulfuric acid as a refrigerant, while still others in later years used ammonia, methyl chloride, sulfur dioxide, and other highly toxic, flammable substances. Needless to say, accidents with these machines were common.

And the refrigerators weren’t widely used. Even in the early 20th century, people usually had to get produce fresh daily and consume it almost as quickly. They made frequent trips to the butcher’s shop, and the milkman completed daily rounds. Fortunate people who had the money to spare for weekly ice deliveries were able to keep food for two or three days in an icebox.

Improvements

Fred W. Wolf created the first commercially successful electric home refrigerator, which was produced in the United States and went on sale in 1913. Wolf’s creation, dubbed the Domelre, was an air-cooled unit made for mounting on top of an ice box. In 1915, Alfred Mellowes worked in a backyard wash house to design another electric refrigeration unit, but this one differed in that a compressor sat in the bottom of the cabinet. Read the rest of this entry »

Refrigeration and Freezing for Food Preservation

Because food is so important to survival, food preservation is one of the oldest technologies used by human beings. There are many different preservation techniques commonly used today, including:

• Refrigeration and freezing : Canning : Irradiation : Dehydration : Freeze-drying : Salting : Pickling : Pasteurizing : Fermentation : Carbonation : Cheese-making : Chemical preservation

The basic idea behind all forms of food preservation is either:

• To slow down or completely stop the activity of disease-causing bacteria
• To kill the bacteria altogether Read the rest of this entry »

Diagnosing Walk-in Coolers & Freezers Problems

A systematic approach to walk-in cooler and freezer maintenance is the technician’s best guide.

The ubiquitous walk-in cooler or freezer is an essential part of many cafeterias, restaurants and convenience stores. It is also a large energy user in these facilities but is rarely considered until problems emerge.

Problems include failure to maintain pressure and compressor failure, both of which can result in expensive losses to the products stored in the cooler. These problems, as well as unnecessarily high energy use, can be avoided by observing equipment and taking corrective action.

Evaporators
Moisture from the air freezes onto the evaporator coils (the cooling coils in the freezer) and forms an insulating barrier to heat transfer. Airflow also decreases as the passages narrow due to ice buildup. Each evaporator has a defrost cycle to melt frost/ice that has built up on the evaporator coils. Water from the melted ice is drained from the freezer . . . ideally. Read the rest of this entry »

Preventative Maintenance for Refrigeration Systems

Suggested Refrigeration Systems Preventative Maintenance

Refrigeration systems are critical in the foodservice industry. It is very important to provide maintenance on your cooling systems to help prevent them from clogging or breaking down, which could lead to spoiled food, rotten food, etc. The following guidelines are provided from Heatcraft’s Operation & Instruction Manual.   By following these preventive maintenance steps, it does not guarantee your unit will not break down. However, by taking care and maintaining your refrigeration systems your unit is less likely to have problems.

Preventive Maintenance

Unit Coolers

At every six month interval, or sooner if local conditions cause clogging or fouling of air passages through the finned surface, the following items should be checked.

Read the rest of this entry »

Hard to Open Doors and Pressure Differences in Your Walk-in Box

Improper fixes to hard-to-open doors can cause ice and frost build-up, water dripping on
floors, freezing around door seals and unusual icing patterns in and around the refrigeration equipment.

Nature’s Basics

The physical nature of air causes a cooler or freezer to have a negative pressure compared to the
outside air. This is due to the contraction of the air as the temperature drops. The pressure of the air in a
sealed box will decrease by 0.3 psi for every drop in temperature of 10 degrees Fahrenheit.
Note: This negative pressure is not caused by the refrigeration equipment removing air. The evaporator fans just cool the air and push it around the box. They don’t have any exhaust venting or “makeup air” being brought in from the outside (like they do in air conditioning systems).

Check it Yourself

The most dramatic pressure change happens when the door is closed. Warm air that entered a cold
freezer will be cooled within seconds by contact with the ceiling, walls and product. If the average air
temperature quickly drops from 40 to 30 degrees, the pressure drops by 0.3 psi. That’s 43 pounds per square
foot, over 800 pounds of force on a normal size door. The door will be impossible to re-open until the
pressure is equalized.
Note: The bigger the size of the door and the more airtight the box, the more dramatic it will be. Read the rest of this entry »

New! Copeland Scroll Outdoor Condensing Unit

Copeland now carries outdoor condensing units for the food service industry. There new light weight, slim shaped units are available in medium and low temperatures ranging from 2 – 6 horsepower.

Copeland Scroll Outdoor Condensing Units are perfectly suited for walk-in cooler and freezer applications. All units integrate the many benefits of the Copeland Scroll compressor technology, fan speed control and Copeland Performance Alert™ diagnostic controls, and are available in 208/230 single-phase and 208/230 three-phase voltage applications.

Scroll compressors offer the highest energy efficiency levels to lower energy bills. With integrated controls that optimize fan motor speed to maximize the heat transfer through over-sized condenser coils, additional energy savings are achieved. The average energy savings for end-users is $350 per year for a 3HP medium temperature unit, however this number could be greater depending on the application.

Read the rest of this entry »

Types of Refrigeration Systems Used in Walk-ins

Refrigeration systems consist of a condensing unit and an evaporation coil. The condensing unit is located outside the walk-in and the evaporator is located inside the walk-in. The compressor compresses gas to a liquid. The liquid is then pumped through the condensing unit coil while a fan blows outside air through the coil. Gas is condensed to a liquid and is then pumped through a small copper pipe into the walk-in to the evaporator coil. There, through the expansion valve located in the evaporator coil the liquid is allowed to expand back into a gas. The expansion of the liquid to a gas causes a rapid chilling of the evaporator coil. Since heat always flows toward cold, inside the walk-in air is blown across the evaporation coil to let the coil absorb heat from inside the walk-in. The gas is then allowed to exit the walk-in through a larger copper pipe to the condensing unit where it is once again compressed and cooled to a liquid state and returned to the evaporator coil inside the walk-in. There the cycle is started over.

The new EISA law requires all new walk-ins be equipped with high efficiency motors to be compliant. These cost a little bit more but save you money in the long run. Some suppliers may try to sell you non EISA compliant refrigeration systems. To be compliant with the law and purchase the best lifetime value always ask for EISA compliant equipment.

1. Remote Systems - Remote systems are the least expensive systems to purchase. They consist of a condensing unit, evaporator unit and misc. parts such as expansion valve, site glass, dryer, pump down solenoid thermostat, and on freezers a timer and drain heater to install the system. They require the use of a licensed refrigeration installer since they are pumped down and charged with refrigerant gas on site. The installer will also charge for any other parts needed for the install such as copper pipe, pipe insulation, connectors, and electrical. They are less expensive systems to buy with the walk-in but may cost more over all depending on what the going hourly rate is with the installer and the cost of the parts he provides. They also provide an advantage by allowing the condensing unit to be located outside the building. There the condensing unit can dump its heat without adding extra heat to the building and air conditioning systems. Read the rest of this entry »