Why do you need a UPS on a Pharmaceutical Refrigerator

Selecting a UPS for pharmaceutical refrigerators. What factors to consider when choosing backup power systems for vaccine refrigerators. Keeping temperature-sensitive pharmaceutical products at their specified storage temperature is critical in order to assure their quality and safety when administered to patients.

In the case of a power outage, a non-protected refrigerator will slowly increase its internal temperature. The rate of change will depend on the quality of its sealing and insulation. A typical refrigerator would maintain its internal temperature for around 4 hours in the event of a power cut if the door remained closed. But this is not an ideal situation, as it means that no medicine can be taken out of the refrigerator during the outage. Moreover, if the power loss lasts longer, the products may have to be discarded due to breaking the cold chain storage. Temperature excursion incidents such as this can cost thousands in damaged products, not to mention disruptions in distribution and vaccination programs.

Compliance with Vaccines For Children (VFC) program.

VFC providers must ensure that the temperature of the freezer is at or below 5°F (-15°C) consistently, and refrigerators between 35°F and 46°F (2°C to 8°C). These requirements still apply during a power outage. According to the Center for Disease Control (CDC), VFC providers must have temperature monitoring devices in each storage unit that will continually show the active temperature and have a downloadable log.

Some recent medical refrigerators now feature embed monitoring and data logging functions. Despite the refrigerator being able to keep the cold for several hours in case of power loss, all the alarms and data logging would stop working. Regulations require constant data logging and event logging for traceability. The loss of tracking data can lead to discarding all of the products stored in the refrigerator. Without backup power, the loss risk is quite high. Temperature-sensitive medicines often have to be discarded because of power outages.

A study published in the Journal of Clinical Pharmacy and Therapeutics conducted by the University of Canberra, Australia, found that the average cost for a pharmacy in the event of a power outage is AUD$13,168. If 10% of pharmacies in Australia suffered significant power outages, it would equate to a total of AUD$7.6M. In early 2017 a hospital and pharmacy in Western Australia suffered repeated power outages, which led to the discarding of thousands of dollars worth of medicines. It also left the town vulnerable to medicine and vaccine shortages. The study also found that vaccine losses in Australia amount to AUD$16M alone.

Power outages and refrigerated medicines: The need for better guidelines, awareness and planning. Kosari S, Walker EJ, Anderson C, et al. Power outages and refrigerated medicines: The need for better guidelines, awareness and planning. J Clin Pharm Ther. 2018;43:737–739. https://doi.org/10.1111/jcpt.12716

Medical offices who are administering vaccines are now required to have backup power for their refrigerators.  The CDC also recommends that vaccine refrigerators have emergency backup power.

The use of an Uninterruptible Power Supply (UPS) to keep the refrigerator powered at all time is an obvious choice for the safety of the medicines and for preventing huge costs due to the loss of the products.

Important information to verify in order select your UPS

To correctly select your UPS, two specifications of the refrigerator are important to consider which determine the UPS specifications.

  1. Average power consumption rating.
  2. Compressor Startup Current

The refrigerator or current rating and energy consumption are usually indicated on the nameplate of the refrigerator as shown below.

Haier Pharmaceutical Refrigerator name Plate

Power Consumption Ratings

Most laboratory or pharmaceutical grade refrigerator manufacturers specify their products’ average energy consumption in terms of KWh for 24h period. These figures are around 1KWh/24hr for a small system in a typical pharmacy. ENERGY STAR® Program has defined a methodology to calculate this power consumption

The consumption estimation is based on multiple door opening and closing events every hour during an 8hr day. This allows you to determine the UPS runtime and requirements for maintaining the power to the refrigerator during a long power outage.

For example, a 120V refrigerator consuming 3.3kWh / 24h, with a rated current of 2.6A will consume about 137 Wh per hour which converts to 1.2Ah (137 ÷ 120). The table below shows the minimum battery capacity required for the desired runtime until the batteries are depleted

Runtime8 hrs12 hrs24 hrs36 hrs
Battery Capacity10 Ah15 Ah30 Ah45 Ah
UPS Battery Capacity and Runtime

Compressor Startup Current

Another important value to note, when sizing the UPS for your refrigerator backup power, is the compressor start-up current (Amps). When a compressor motor starts, it will draw much more current than when it is running. Therefore, you have to make sure that the UPS will be able to provide this surge current so the compressor can start. Otherwise, it will be undersized and the compressor will fail to run. The nameplate will indicate the current rating when the compressor motor is running. The startup current is usually 5x the rating current for a new unit, but it can get as much as 10x. Ageing compressors require more startup current, especially if not properly serviced.

As in the example above, the current rating of the refrigerator is 2.6A, you should size your UPS so it is able to output 10x the power, which 3.12 kW:

10 × 2.6A × 120V = 3,120 W

Note: If you are using Ultra Low-Temperature Freezers (ULTF)

due to the very low temperatures that these freezers have to generate, they consume much more energy, a conducted by the University of California on ULTFs showed that they can consume from 15kWh/day to 32kWh/day. The UPS required for these types of freezers, therefore, need large battery capacity but also large surge power output.

Some UPS manufacturers will give two output power specifications for their UPS : the output power for continuous power supply and the surge output power for short peaks of power demand; refer to the latter if available to verify that it is suitable for your refrigerator.

UPS Selection

If your UPS is not sized properly, this could result in the compressor not able to start, therefore rendering it ineffective at powering the refrigerator and maintaining temperature.

A typical refrigerator compressor has a power consumption of around 200W, and will require a UPS able to provide at least 2kW surge.

In the case you are not able to figure out those two values from your medical fridge, you can use an Amp meter to measure the current and power consumption of your refrigerator, this would give you real-world data to use of sizing your UPS. The below video shows the use of a handheld clamp meter to measure the current draw.

There are some additional features that you might consider when selecting your UPS for better monitoring.

  • Protection against voltage surges or power drops that could damage the freezer’s compressor. Voltage spikes could also be caused by backup generators test and cause damages to the compressors if they are not protected by a battery backup system.
  • Monitoring interface: monitoring the charge state, capacity and runtime of your UPS with a monitoring software would help you to maintain your UPS in perfect condition for the day its installation will be the most important. What would happen if the battery of your UPS is old or half full and needs to be replaced? The monitoring software can send you alarms for preventive maintenance
  • Multiple input sources: prefer a UPS with the ability to connect to multiple sources, so you can use alternate power sources to recharge your UPS (solar, wind, fuel generator)

Response plan in case of an extended power outage

Now that you have selected your UPS for your medical refrigerator, are you prepared for a power outage that lasts much longer than the UPS runtime?

The CDC recommends having a plan in place to move the vaccines to another facility during extended power outages. “Every facility should have detailed written protocols for routine and emergency vaccine storage and handling and they should be updated annually.

Here is some advice to prepare a response plan in case of a prolonged power outage.

Know Your Electrical Grid

  • What is your utility company contact information?
  • Where are you located on the distribution network?
  • Are you a priority facility for your utility company in case of a power outage?
  • Are your key resources powered by backup UPS?
  • Do you have a secondary power backup? 

The use of both UPS and a secondary backup fuel generator together will keep your refrigerator in action much longer. The UPS being used while the generator takes up the power, especially if you do not have an automatic transfer switch.

  • Do you have a monitoring system to send you alarms when a power outage is detected?

Knowing when your refrigerator is no longer powered or is running on backups, allows you to put into action your prevention plans to keep the medicines safe.

  • Emergency backup storage and transfer

In the event of a prolonged power outage that exceeds your UPS capacity and the absence of a secondary backup power system

  1. Identify a facility with appropriate storage capability where you can transfer your temperature-sensitive pharmaceuticals, this can include a local hospital, pharmacy, long-term care facility, or the Red Cross
  2. Identify suitable transportation vehicle such as a refrigerated truck for large inventories
  3. Have an adequate supply of insulated packing materials such as isolated containers, iced packs, etc.
  4. Prepare mobile temperature data loggers in order to keep track of the temperature of the vaccines during the transfer
  5. Train your staff, so they are prepared in the event of a power outage

The CDC provides guidelines for emergency transport of vaccines.

Some Suitable UPS’s

Below is a list of some UPS systems that would be suitable for use on a pharmaceutical refrigerator.


Medi-Products manufacture UPS that are dedicated to medical installations, they offer UPS for different types of installations: wall-mounted standalone, wall-mounted hardwired and mobiles systems. The UPS power range from 1.2kW to 4.4kW and capacities from 100 to 800 Ahr

Rolex Medical

Rolex Medical is a refrigerator and freezer manufacturer which also provides some UPS. To note, they also include a Power Factor Correction, which helps to reduce the load of high-current compressor starts and extending the life of the components.


Geneforce provides a wide range of mobile indoor UPS that can be used with refrigerators from 2kW to 6.8kW.

Power Inspired

Power Inspired is a general UPS manufacturer with a large range of UPS with some models that could be suitable for medical refrigerators such as their VIS or VFI series.


TempArmour is a refrigerator and freezer manufacturer which are often coupled with Xantrex standalone UPS with 1.8kW output power and up to 200 and 400Ahr batteries. They have DC input for renewable energy source input, AC sockets output with hardwire options


There is a large choice of UPS’s. As one does not fit all, the selection of a suitable UPS will depend on your refrigerator specifications, size and location. This will define the requirements of the UPS for maximum runtime in case of a power outage.

Additional features such as multiple input sources and output socket, or power factor correction are to be considered when selecting your UPS. A monitoring system that can alert when battery power is low and the status of the mainline power is also useful.


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