| Abstract | U ovom diplomskom radu prikazan je postupak projektiranja dizalice topline koja radi na principu izmjene topline zrak-voda za potrebe grijanja i hlađenja proizvodnog pogona na području grada Sesveta. U režimu grijanja kompaktna dizalica topline radi u temperaturnom režimu 50/40°C, a u režimu hlađenja radi u temperaturnom režimu 7/12°C. Korisna površina pogona za proizvodnju i testiranje rashladnih agregata i dizalica topline iznosi 660 m2 . Kao temelj proračuna bilo je potrebno izračunati projektno toplinsko opterećenje pogona prema normi HRN EN 12831 i projektno rashladno opterećenje pogona prema normi VDI 2078. Reverzibilna dizalica topline sastoji se od dva rashladna kruga koja koriste R290 (propan) kao radnu tvar. Hidraulički krug, koji prenosi toplinsku i rashladnu energiju do potrošača, koristi vodenu otopinu etilen-glikola kao ogrjevni/rashladni medij. Hidraulički krug čini dvocijevni razvodni sustav sa ventilokonvektorima smještenim na predložene lokacije unutar pogona. Rezultati proračuna toplinskog i rashladnog opterećenja pokazali su da projektno toplinsko opterećenje iznosi Φi = 61,8 kW pri vanjskoj projektnoj temperaturi od -9,8 °C, a projektno rashladno opterečenje iznosi Φhl = 30,19 kW pri vanjskoj projektnoj temperaturi od 36,1 °C. Uzevši u obzir da je toplinsko opterećenje veće od rashladnog, dizalica topline dimenzionirana je prema toplinskom opterećenju. Međutim, uzevši u obzir da je temperatura zraka (kao toplinskog spremnika) varijabilna na dnevnoj, odnosno satnoj razini, dizalica topline projektirana je za vanjsku temperaturu od -3 °C u režimu grijanja kako sustav u konačnici ne bi bio predimenzioniran. Na taj način, dizalica topline može dati 50,8 kW toplinskog toka za potrebe grijanja. Kad vanjska temperatura padne ispod -3 °C, nedostatak toplinskog toka prema potrebi nadoknađuju električni grijači, smješteni unutar akumulacijskog spremnika, koji dogrijavaju medij do polazne temperature. Odabirom ovakve izvedbe, dizalica topline radi učinkovitije. |
| Abstract (english) | This master’s thesis presents the process of designing a reversible heat pump that operates on the principle of air-to-water heat exchange for heating and cooling of the production facility located in Sesvete, a city district of Zagreb. In heating mode, the compact heat pump operates at a temperature regime of 50/40 °C. In cooling mode, it operates at a temperature regime of 7/12 °C. The useful area of the production hall, including the testing facility, equals 660 m2. The basis for calculation and design was to determine the design heating load of the facility according to the HRN EN 12831 standard. Likewise, the design cooling load was calculated according to the VDI 2078 standard. The heat pump chosen for this facility consists of two refrigeration circuits which use R290 (propane) as a refrigerant. The required heating or cooling energy is distributed through the facility using a 2-pipe system which uses a mixture of water and ethylene-glycol as an energy transfer medium. Furthermore, fan coils installed at proposed locations transfer the heating or cooling energy into the rooms of the facility. The results of the thermal load analysis indicated a design heating load of Φgr = 61,8 kW at the outside temperature of -9,8 °C. Likewise, cooling load analysis indicated a design cooling load of Φhl = 30,19 kW at the outside temperature of 36,1 °C. According to these thermal loads, calculations were made to dimension the components of the refrigeration circuits and the hydraulic circuit which includes an accumulation tank and two circulation pumps. Considering that the heating load is greater than the cooling load, the heat pump was designed according to the design heating load. However, considering that the outside air temperature is variable throughout the day, the heat pump was designed for the outside air temperature of -3 °C instead of -9,8 °C in heating mode in order to avoid oversizing of the system. Therefore, the heat pump can supply 50.8 kW for heating needs at the outside temperature of -3°C. When the outside temperature drops below the design temperature of -3 °C, electric heaters installed within the accumulation tank supply the remaining heating load as needed before entering the distribution system. This results in heat pump operating more efficiently. |
