Potential energy savings in refrigeration systems using optimal set-points

Abstract

Absfmcf-Energy efficiency of refrigeratinn systems has gradually been improved with help of control schemes utilizing the mom flexible components. This paper proposes an appmach in line with this Wnd, where a suboptimal condenser pressure is found in order in minimize the energy consumption. The objective is to give an idea of how this optimization scheme works as well as to show what amount of energy it is possible to s v e . A steady state model of a simple refrigeration system will be used as a basis for the optimization.

Minimal Energy Efficiency Indicators for Poultry Industries

“…Advances in component technology, such as electronic controllable expansion valves and variable speed control of compressors and fans, make possible to apply more advanced control systems that achieve better performance, in addition, better EE [14]. The industry has at its disposal sensor systems technology for the cooling circuit with sensors supply voltages from 0 to 5 volts or 4 to 20 mA.…”

The role of maintenance in energy saving in commercial refrigeration

“…Larsen and Thybo (2004) Energy saving in commercial refrigeration describe a means for calculating the optimal pressure difference across the compressor in terms of energy consumption resulting in a 30 per cent decrease in energy consumption. Yu and Chan (2008) propose a model for analysing control procedures for condenser fans and extend this to provide fan control based on load which can provide performance improvements in the range of 7.8-113.2 per cent.…”

A method for online steady state energy minimization, with application to refrigeration systems

“…Examples of that are given in (Jakobsen et al, 2001) and (Larsen and Thybo, 2004). The goal of an energy optimization is to keep the cooling capacity (Q e ) constant while lowering the overall power consumption to a minimum at steady state.…”

“…These constrains (Q e = Const, SH = Const) reduce the degree of freedom in the minimization till two, which means that the evaporator and the condenser pressure should be manipulated in order to find the minimal power consumption. An important point that is stated in (Larsen and Thybo, 2004) and (Jakobsen et al, 2001) is that the optimal condenser pressure is practically independent of the current evaporator pressure. This means that the evaporator and condenser pressure can be optimized individually as two 1 degree of freedom optimization problems in order to reach the global optimum (the maximal efficiency).…”