LARGE-SCALE HEAT PUMPS IN SUSTAINABLE ENERGY SYSTEMS: SYSTEM AND PROJECT PERSPECTIVES
Sustainable Development of Energy, Water and Environment Systems
This pa per shows that in sup port of its abil ity to im prove the over all eco nomic cost-ef fec tive ness and flex i bil ity of the Dan ish en ergy sys tem, the fi nan cially fea sible in te gra tion of large-scale heat pumps (HP) with ex ist ing com bined heat and power (CHP) plants, is crit i cally sen si tive to the op er a tional mode of the HP vis-à-vis the op er a tional co ef fi cient of per for mance, mainly given by the tem per ature level of the heat source. When us ing ground
... us ing ground source for low-tem per a ture heat source, heat pro duc tion costs in creases by about 10%, while par tial use of condensed flue gas ses for low-tem per a ture heat source re sults in an 8% cost re duc tion. Fur ther more, the anal y sis shows that when a large-scale HP is in te grated with an ex ist ing CHP plant, the pro jected spot mar ket sit u a tion in The Nordic Power Exchange (Nord Pool) to wards 2025, which re flects a grow ing share of wind power and heat-sup ply con strained power gen er a tion elec tric ity, fur ther re duces the op era tional hours of the CHP unit over time, while in creas ing the op er a tional hours of the HP unit. In re sult, an HP unit at half the heat pro duc tion ca pac ity as the CHP unit in com bi na tion with a heat-only boiler rep re sents as a pos si bly fi nan cially feasi ble al ter na tive to CHP op er a tion, rather than a sup ple ment to CHP unit op er ation. While such re vised op er a tional strat egy would have im pacts on pol i cies to pro mote co-gen er a tion, these re sults in di cate that the in te gra tion of large-scale HP may jeop ar dize ef forts to pro mote co-gen er a tion. Pol icy in stru ments should be designed to pro mote the in te gra tion of HP with lower than half of the heat ing ca pac ity of the CHP unit. Also it is found, that CHP-HP plant de signs should al low for the uti li za tion of heat re cov ered from the CHP unit's flue gas ses for both con cur rent (CHP unit and HP unit) and in de pend ent op er a tion (HP unit only). For in de pendent op er a tion, the re cov ered heat is re quired to be stored.