Water-to-water heat pump for heating and cooling of residential building

Diplomski rad predstavlja proračun dizalice topline voda-voda za grijanje i hlađenje stambene zgrade na otoku Krku. Stambeni prostor je korisne površine 328 m2 kojeg čine prizemlje i dva kata. Dizalica topline radi u monovalentnom načinu rada s podzemnom vodom kao izvorom energije. Ogrjevno/rashladna tijela po prostorijama korištena u ovom KGH sustavu su ventilokonvektori. Toplinsko opterećenje stambene zgrade određuje se prema postupku iz norme HRN EN 12831. Pri proračunu projektnih toplinskih gubitaka zgrade promatraju se transmisijski i ventilacijski toplinski gubici. Ukupni toplinski gubici zgrade zimi iznose 12,5 kW. Toplinsko opterećenje zgrade ljeti računa se prema normi VDI 2078, a podijeljeni su na unutrašnje i vanjske toplinske dobitke. Ukupni toplinski dobici ljeti iznose 10,8 kW. Potrebna toplinska energija za grijanje određuju se prema normi HRN EN ISO 13790. Proračun prema normi HRN EN ISO 13790 provodi se tako da se cijela zgrada tretira kao jedna zona. Ukupna godišnja toplinska energija za grijanje zgrade iznosi 12884 kWh što iznosi 39,28 kWh/m2 godišnje te se time zgrada svrstava u B energetski razred. Temperaturni režim grijanja je 47/42 °C pa je prema tome odabrana temperatura kondenzacije od 50 °C. Za izvor topline u obliku podzemne vode koja je na konstantnoj temperaturi od 13 °C odabrana je temperatura isparavanja od 4 °C. Kao radna tvar za krug dizalice topline odabrana je prirodna radna tvar R290 (propan), ponajviše zbog malog utjecaja na okoliš. Učinak isparivača je izračunat i iznosi 9,8 kW. Površina izmjene topline pločastog isparivača iznosi 1,26 m2, a pločastog kondenzatora 1,11 m2. Provedena je energetsko-ekonomska analiza dizalice topline voda-voda koja ukazuje na izrazito visoke investicijske troškove sustava dizalice topline. Naime, uz duplo manje troškove pogona u odnosu na konvencionalne sustave cijena investicije je tolika da će dizalica topline voda-voda tek nakon 20 godina rada biti isplativa. Ipak, ekološka analiza je pokazala nešto bolju sliku o dizalicama topline koje u odnosu na konvencionalne sustave grijanja imaju nekoliko puta manju emisiju CO2.Master thesis represents the calculation of the heat pump water-water for heating and cooling of residential building on the island of Krk. Usable area of this building is 328 m2 which consists of three floors. Heat pump works in mono mode with ground water as a source of energy. Heating/cooling units on the premises used in this HVAC system are fan coils. The heat load of the residential building is determined according to the procedure of the standard EN 12831. When calculating projected heat losses of the building, transmission and ventilation heat losses are observed. The total heat loss of the building in winter is 12,5 kW. The heat load of the building in summer is calculated according to VDI 2078. The heat load is divided into internal and external heat sources. The total heat gain in summer is 10,8 kW. Energy use for heating is determined according to EN ISO 13790. Calculation according to ISO 13790 is carried out so that the whole building is treated as one zone. Total annual energy use for heating the building is 12884 kWh, which is 39,28 kWh/m2 per year, thereby building is classified as B energy class. The temperature mode of heating is 47/42 °C and accordingly to that condensation temperature is 50 °C. For the heat source in the form of ground water which is at a constant temperature of 13 °C selected vaporization temperature is 4 °C. Natural refrigerant R290 (propane) is chosen for the heat pump, mainly due to the low environmental impact. Evaporator power is calculated to 9,8 kW. Heat transfer surface of the plate evaporator is 1,26 m2 and 1,11 m2 of the plate condenser. Conducted energy-economic analysis of the heat pump water-water points out an extremely high investment costs of the system. In fact, with half the operating costs compared to conventional heating systems, investment is such that after 20 years of operation heat pump water-water will be profitable. However, environmental analysis showed a slightly better picture of the heat pumps, which in comparison to conventional heating systems have several times less CO2 emissions