CO2 hydrate cooling system and LCC analysis for energy transportation application

• The CO2 hydrate system is an economic alternative solution to the conventional DCS.
• The optimum pipe diameters for CO2 hydrate and DCS are 200 and 400 mm, respectively.
• The pump power rate of the DCS is 2.5 times higher than that of CO2 hydrate system.
• Total LCC for CO2 hydrate cooling system is only a half of that for the DCS.

Recently, many researchers have investigated alternative refrigerants in order to replace CFC and HCHC refrigerants. One of the alternative refrigerants is CO2 hydrate slurry that has a large latent heat (507 kJ/kg). In this study, we carry out an economic evaluation of the CO2 hydrate cooling system by Life-cycle cost (LCC) analysis technique. LCC consists of the key parameters such as initial cost (IC), energy cost (EC) and maintenance cost (MC). Total LCC for a district cooling system (DCS) and CO2 hydrate cooling systems is compared for long distance energy transportation application. It is found that the total LCC for the CO2 hydrate cooling system is only a half of that of the DCS based on the cooling capacity of 5000 RT, the transportation distance of 10 km, and the service life of 20 years. It is concluded that the optimum transportation pipe diameters for CO2 hydrate and DCS are 200 mm and 400 mm, respectively, for the present basis conditions. It is also concluded that the effect of the pump power rate of the DCS on the total LCC is 2.5 times higher than that of the CO2 hydrate cooling system.