Flashcards
2) Psychometry and Air Conditioning
Flashcards do conjunto (17)
- 1What is the psychrometric chart?A graphical representation of:
- thermodynamic properties of moist air
- air conditioning processes
Not very accurate but convenient for quick estimatationgs
101325 Pa (760 mm Hg) from -10 ~ 60°C - 2Percentage saturation lines graph and equation
- 3Specific enthalpy lines graph and equation
- 4Wet bulb temperature lines graph and equation
- 5Specific volume lines graph and equation
- 6On psychrometric chart: - Find state point using temp and percentage saturation - Moisture contentFind temperature at 15C, draw vertical line (state point).
Draw horizontal right line from state point to find moisture content, to also get partial pressure.
- 7On psychrometric chart: - Dew point temperature - enthalpyDraw horizontal left from state point to find dew point of moist air, then vertical line down for temperature reading.
Move ruler from state point to the right so points on each ruler are the same e.g. 35 to find enthalpy.
- 8On psychrometric chart: - Wet bulb temperature - Specific volumeWet-bulb temperature by following enthalpy line to the left, draw vertical line down to get temperature reading.
From state point you can estimate specific volume.
- 9Steady flow process of typical summer air conditioning system
- 105-->1 sensible heating processNote heat gain into reheater, no change in moisture content. Dry air is also constant.
- 114--->5 cooling and dehumidification processNote heat and moisture reduced from cooler, moisture is now balanced.
- 122+3--->4 mixing processwhere mad,2 = mda,2,recirculated + mad,2,exhaust
- 13—Mass of dry air is in balance (ingoing and outgoing air). When air supply is supplied into the room air coming from outside will mix with inside air, also from infiltration. Energy balance equation, people, light, laptops release heat into the room, plus energy associated from moisture transfer from equipment.
- 14Room sensible and latent heat load
- 15Supply air condition and ratio method 1:
- 16Supply air condition and ratio method 2:Make position of room condition (point 5, 50% 22C).
Use lower section of protractor to draw line from pint to indicating process from 1 to 2. Draw a line parallel to this line, crossing point 2 (light blue line) called room ratio line, slope corresponding to room ratio. Chose any temperature e.g. 18C and draw it on the chart. Draw horizontal line from point 1 to moisture content).
- 17Winter air conditioning system:
Informações
- Descrição
- YR 3 Thermodynamics 2 FlashCards sobre 2) Psychometry and Air Conditioning, criado por Alice Kimpton em 07-10-2019.
- Criado por
- Alice Kimpton · out 2019
- Atualizado
- 7 out 2019
- Visualizações
- 25
- Avaliação