A research study s ubmitt ed in partial fulfill ment of the requirement for the degree of Master of Engineering.

Research Studies Project Report (M.B.A.) - Asian Institute of Technology, 1992

This report presents t h e resul ts of a feasibility study of ice storage for process cooling in three industrial plants in Th ai land. The s t.ud ied i nd ustri al plan ts a.re Aj .inomo to Co.Ltd, Nestl e (Thai l and ) and Bangkok Live Stock Co. Lt d (C.P Group ) . Aj inomoto p l ant comes under TOD rate structures.The ice storage system is Bized b y con sidering option I, i. e , c h arging of ice storage d u ring off - peak hours only and option II, i.e, charging of ice storage during off-peak and partial peak hours to s hift the peak refrigeration electricity demand to off-peak and partial peak period. An ice storage in Ajinomoto plant operating under options I and II would have a simp l e payback periods of abou t 6 and 5 years respectively under the present electricity rate structure. Nest l e (Tha i land ) comes under the f l at rate structure. The power consumption of refr i gerat i on system is about 20 % of the tota l pl ant electrical demand. Ice storage is sized for the exi s t ing plant and for a new plant of t he same cooling capacity . I n this plant, under t he present rate structure, ice storage for t he existing plan t is not economical l y feas i bl e but for a new pl ant it woul d be feasible. In Bangkok Live Stock Co . Ltd, the ice storage is i nstalled to provide the i ce maker and air-conditioning cooling l oad by usi ng the extra capacity of high stage compressors, i nstead of conventiona l chillers. In this plant the existing ice storage is more economically attractive as compared to alternat i ve conventional system to provide the same cool ing l oad. The investment cost of ice storage was compared with demand charge savings using s imple paybacl< periods, net present va l ue and internal rate of ret ur n . It was found that in Ajinomoto pl ant under t he present, TOD 1 and TOD 2 rate structures, option II, storage system presents a better economi c feasi bi lity, especia l ly when demand charge during peak per i od is higher and energy charge during off- peak period is smaller.