All mechanical freezers work by exchanging heat inside the freezer with the environment outside. The part that actually does the heat exchange is called the condenser. As its name implies, the condenser condenses gaseous coolant into liquid and circulates it back through the system, exchanging heat.
Most condensers are air-cooled, meaning they vent excess heat into the surrounding air and use a system of fans to keep the components cool.
A water-cooled condenser operates differently. It uses a continuous supply of (possibly chilled) water to remove heat. Water-cooled condensers are typically more efficient than air-cooled condensers. They also decrease heat output from the freezer unit into the room.
How do benefits like these translate into cost savings for biorepositories?
At Thermo Fisher Scientific, we manufacture water-cooled condensers as a factory-installed option for our line of -86°C upright freezers, and we’ve tested the condensers to determine how much electricity and heat these devices can save. The results are impressive:
A water-cooled condenser option in conjunction with a Thermo Scientific -86°C freezer can save up to 17% in energy consumption.
Water-cooled condensers are more efficient than their air-cooled counterparts, resulting in lower electricity usage for ultra-low temperature freezers. Specifically, we found the energy consumption was 17% lower when a water-cooled condenser was installed in a 500 box capacity freezer; the savings for other sizes varied from 6% to 14%.
A water-cooled condenser option in conjunction with a Thermo Scientific -86°C freezer can reduce heat output into the lab by up to 90%.
With a water-cooled condenser, excess heat is directed down the drain instead of into laboratory space. We found the decrease in heat output was up to 90% depending on the freezer size and operating mode. By reducing heat output, you can decrease expenses for cooling the lab and you may be able to better optimize storage space, because freezers can be placed closer together.
In short, our results show that a water-cooled condenser option in conjunction with a Thermo Scientific -86°C freezer can save up to 17% in energy consumption and reduce heat output by more than 90% — and all without compromising sample protection.
Like virtually every aspect of biobanking, water-cooled condensers aren’t a “fix it and forget it” solution, however. An interruption in the water supply will make the condenser unable to exchange heat, potentially damaging the equipment and raising the internal temperature of the freezer if the problem isn’t dealt with quickly. It’s worth noting, though, that Thermo Scientific freezers are designed to protect samples at all costs, and a similar problem can arise with standard air-cooled condensers if an exhaust vent is blocked for an extended period of time. As we’ve mentioned before, you need a back-up and alarm system for optimal protection of irreplaceable samples. A wireless monitoring system – which can send alerts in the case of warnings, failures or alarms – is ideal for any biobank working with samples that need to be preserved with a tight temperature tolerance.
For more information on water-cooled condensers for ultra-low temperature freezers, check out this Smart Note. To request a quote, or view other accessories available for ULT freezers, visit Thermo Scientific.