There are several modes of operation when discussing thermoelectric applications for beverage cooling:
1. Temperature Maintenance
2. Cool Down and Sustain Mode
3. On Demand
Thermoelectric Cooling can be Applied to Beverage Refrigeration
This mode of operation describes the process where beverages are entering the cooler at, or below, the desired temperature. The loads associated with maintenance are typically in the single digits of watts for a small, fully insulated enclosure and range upward depending on the size and visual requirements of the enclosure. In this mode, thermoelectric assemblies are sensible and are a good fit for most applications. Typical desired temperatures are greater than 3°C and less than 7°C for carbonated beverages, white wines and water, while slightly higher for red wines, approximately 13°C. Typical ambient classifications include indoor applications at 25°C, outdoor applications at 32°C and some extreme conditions approaching 41°C. Many of these profiles are well suited for thermoelectric applications as evidenced by the success of small dorm style coolers and in home wine chillers. Extreme ambient temperature applications may require extraordinary insulation techniques or two-stage thermoelectric designs. Humidity conditions, the quality of the door seal, air exchange and visual cosmetics will all factor in the load on the system.
Cool Down and Sustain Mode
The cool down and sustain mode of operation include all the loads and temperature requirements for temperature maintenance, plus the added need to pull down the beverages from the ambient, or storage temperature, in a specified amount of time. This is still within the capability of thermoelectric systems, especially if the desired time-to-temperature is over an extended period of time, i.e. cool down a case of beverages overnight. Thermoelectric systems may not compete in this mode with compressor based systems if the beverage unit/can count is too high or the temperatures are extreme.
On Demand beverage cooling can be quite challenging, even for compressor based systems. Typically, for very high demand applications such as sporting venues, ice is accumulated prior to the event to help store and then later distribute some of the load capacity. Thermoelectric systems have been used successfully in On Demand applications to keep the dispensing mechanisms at the temperature for remote cooling configurations. Thermoelectric systems can be effective at generating ice in indoor applications. Once the high temperature requirement is specified, two- stage thermoelectric configurations are the foundation of the solution.
Thermoelectric systems can be designed to meet the requirements in all of these modes. Design flexibility, small form factors, high reliability and CFC free are all positive benefits when selecting thermoelectric technology. Cost and energy consumptions are the gating factors and should be well understood before selecting thermoelectric technology in this application. Smaller container count and capacity make beverage point of sale applications feasible for thermoelectric systems.
Check out some of our recommended uses for consumer products in our Thermoelectric Survival Guide.