PDF Publication Title:
Text from PDF Page: 014
Buildings 2020+. EnErgy sourcEs heat transmission goes down, the temperature difference between the condensation temperature and the fluid temperature rises. As the temperature of the heating is constant, the condensation temperature must be higher. The compressor must operate at a higher pressure ratio when its volumetric efficiency is reduced and creates a risk of overload. To avoid this, the condenser must be constantly cleaned of dirt and soiling. The logarithmic temperature difference ∆tm between the condensation temperature and the temperature of the heated building is used to calculate the condenser output. The temperature difference between the cooling medium and the refrigerant changes depending on the distance of the flow, but this change is not linear and cannot be used for the calculation. The temperature difference can be described by Eq. (5.11): ∆tm = ∆t1 − ∆t2 (5.11) ln ∆t1 ∆ t 2 Neither heat dissipation nor supercooling is taken into account. The logarithmic temperature difference is therefore the basis for calculations in the condensation area. The heat flow to be discharged by the condenser is made up of the compressor power intake and the heat resources capacity. If this data is unknown, the condenser output can be recorded by measurement. For the underfloor heating (water cooled) condenser, the output is calculated by Eq. (5.12): where: Qc – VF – ρF – cF – tF1 – tF2 – Qc = VF · ρF · cF (tF1 – tF2) (5.12) total output of the condenser (kW), underfloor heating water flow rate (m3/s), underfloor heating water density (kg/m3), underfloor heating water specific heat capacity (kJ/(kg∙K)), underfloor heating water temperature at condenser inlet (°C), underfloor heating water temperature at condenser outlet (°C). Measuring the output of an air-cooled condenser is similar. It should be noted that the specific heat capacity and density of the air depends on the temperature. Values can only be constant for small temperature differences. The condenser output is calculated using the air flow rate by Eq. (5.13): Qc = VA · ρA · cA (tA1 – tA2) (5.13) 158PDF Image | Heat Pumps 978-83-65596-73-4
PDF Search Title:
Heat Pumps 978-83-65596-73-4Original File Name Searched:
Buildings-2020-part2-rozdz5.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |