## 1 Introduction  
In the past few decades, energy crisis and environment problems became serious because of the increasing energy demand and the rapid economic development all over the world. Many efforts have been devoted into developing advanced energy conversion technologies to relieve the current challenging energy situation. For the existing energy sources (such as fossil fuels, solar, biomass, geothermal energy, and nuclear energy) and industrial waste heat sources, various novel energy conversion systems were proposed in place of the conventional ones to improve energy utilization [1]. Among these proposed systems, the supercritical CO2 power cycle (sCO2) is considered to be a promising technology with great potential and competieness owing to its advantages of a compact structure, environmental friendliness and high efficiency [2; 3; 4]. The sCO2 power cycle operates above the critical point of CO2 (31.3 \({}^{\circ}\)C, 7.39 MPa). Due to the dramatic changes of thermodynamic properties near the critical point, the inlet state of its compressor is always designed just above the critical point so that the compressor work can be reduced significantly. Hence, cooling the CO2 before compression process can be beneficial to the efficiency improvement [5; 6; 7]. However, a huge amount of heat is inevitably rejected by the cooler during the cooling process. So, it is worthwhile to reuse this low-grade heat energy through waste heat recovery systems to improve the performance of the sCO\({}_{2}\) cycle [8; 9]. Various waste heat power generation systems were adopted to recover the waste heat of the sCO\({}_{2}\) cycle. [PERSON] et al. [10] applied an Organic Rankine Cycle (ORC) to reuse this waste heat for producing electric power, and compared the combined sCO\({}_{2}\)/ORC system with two stand-alone closed CO\({}_{2}\) cycles. They concld that the addition of ORC could improve the thermal efficiency by 7-12%. [PERSON] and [PERSON] [11] conducted a thermoeconomic analysis for a combined recompression sCO\({}_{2}\)/ORC system. Compared to the stand-alone sCO\({}_{2}\) cycle, the exergy efficiency increased by up to 11.7% and the total product unit cost decreased by up to 5.7% for the combined sCO\({}_{2}\)/ORC system. [PERSON] and [PERSON] [12] compared a transcritical CO\({}_{2}\) cycle (tCO\({}_{2}\)) with an ORC as the bottoming cycle for a recompression sCO\({}_{2}\) cycle. The sCO\({}_{2}\)/tCO\({}_{2}\) system showed a better performance than the sCO\({}_{2}\)/ORC system at a lower pressure ratio, while the latter had a slightly lower total product unit cost than the former. [PERSON] and [PERSON] [13] chose ORC as the bottoming cycle for a simple sCO\({}_{2}\) cycle, a recompression sCO\({}_{2}\) cycle, and a partial cooling sCO\({}_{2}\) cycle. It was concluded that the recompression sCO\({}_{2}\)/ORC system presented the maximum combined cycle efficiency. Some researchers also integrated a Kalina cycle with the sCO\({}_{2}\) cycle to enhance the overall system performances. [PERSON] et al. [14] proposed a combined recompression sCO\({}_{2}\)/Kalina cycle, and found out that the total product unit cost and exergy efficiency of the combined cycle were 5.5% lower and 8.02% higher than those of the sCO\({}_{2}\) cycle. [PERSON] et al. [15] studied the thermodynamic and economic performances for a stand-alone sCO\({}_{2}\) cycle and a combined sCO\({}_{2}\)/Kalina cycle. Results showed that combining the Kalina cycle with the sCO\({}_{2}\) cycle could reduce the exergy destruction significantly. In addition to the combined power generation systems above, establishing combined power and heat/cooling systems can also enhance the overall performance for the sCO\({}_{2}\) cycle.