The potential role of trans-critical CO2 heat pumps within a solar cooling system for building services: The hybridised system energy analysis by a dynamic simulation model

Abstract

The rotary desiccant wheels application in the air conditioning systems are used for the air dehumidification by means of hygroscopic layers for water vapor adsorption. Nevertheless, external heat sources are required for water desorption to close the air treatment cycle. This paper investigates on the possibility to integrate in that cycle a new component, such as the trans -critical CO 2 heat pump, to reduce the contribution of external thermal sources. In so doing, the high temperature waste heat discharged by the heat pump hot sink can be fruitfully exploited. Additionally, a PV array has been added to the typical layout based on the solar collectors, in order to assure the heat pump electrical driving. The energy analysis is carried out by calculating the energy performance indicators of the whole cooling system, simulating it by a dynamic model built in the MATLAB SIMULINK environment. Specifically, an air handling unit has been properly sized to supply cooling load to a reference conference hall of 1200 m 3 , with changes in boundary conditions (i.e. solar radiation, daily temperature and relative humidity variations). Indeed, three different cities representing the most typical Italian climatic zones, have been considered for assessing the proposed technical option suitability.

Off-Design Modeling and Operational Optimization of Trans-Critical Carbon Dioxide Heat Pumps

“…Cao et al reviewed the developments of air source trans-critical CO 2 heat pumps using direct-heated type and recirculating-heated type, whereas Yao et al performed a comparative study of upgraded heat pump systems with different heat sinks [11]. Lo Basso et al studied the potential role of transcritical CO 2 heat pumps within a solar cooling system for building services [12]. Despite the latest advancements, a gap exists concerning the modeling and optimization of trans-critical CO 2 heat pumps operating under different operating conditions throughout the year [13].…”

Biogas upgrading, economy and utilization: a review

“…In addition, this heating process also creates a stream of vapour which functions as a stripping fluid in the process. The vapour stream is then cooled down in a condenser and recirculated so that the CO 2 entrapped in the steam can be released and recovered (Basso et al 2021).…”

Research on defrost characteristics of cascading high temperature air source heat pumps

“…Increase the heat transfer coefficient of the condenser to effectively increase the high temperature stage compressor discharge temperature rate. Excessive high temperature stage compressor discharge temperature is the primary factor limiting the maximum hot water temperature [10]. Dong et al derived a cascade heat pump system with R134a and R410A as high and low temperature stage refrigerants by combining simulation and experiment.…”