Turbine & Compressor

The turbine set up is a double shaft mounted with an expander and compressor each – see picture to the left. The system operates with an internal heat transmission raising the temperature on the inlet to the expander.

Solar collector drives the turbines
The solar devise consists of a traditional thermal solar panel using water with temperatures between 75 - 95°C. An expander, based on a Rankin-process, uses the energy from the solar collector to operate a compressor, which through a Carnot-process cools air in traditional air coolers.

Cooling Process using water
The process uses water as cooling medium both in the expander and the compressor and therefore is environment friendly. The challenge stems from the use of water as a process agent. This means that the expander must have an overheating of between 60-80°C, as well as processing must be in two steps - diagram illustrates the AC-Sun cooling process in the log PH-diagram for water [R718].

This energy recovery from the compressor happened by thermal transmission through heat exchange and increase the cooling capacity from 10 to 15%.

The energy turnover from heat to rotation in the expander demands that the coupled expander/compressor spindles must rotate with 100.000 to 150.000 RPM. The resulting maximum speed of the turbine wheels can not surpass the speed of sound, set at 445 meters per seconds with a temperature of 210°C at the entrance to the expander. This demands special methods of calculation. AC-Sun ApS assesses, that the isentropic degree of efficiency will be around 0,8 or above and therefore will be at the same level as the best products available today.

Compared to other heat-driven cooling processes, AC-Sun is the most energy efficient, meaning that 1 kW heat turns into 1.1 kW cooling. For all other processes, heat utilization is less than half hereof. Moreover, the production price for these installations - unlike the AC-Sun solution - is significantly above market price.