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Confidential

Confidential. Nakatsugawa Works. LOSSNAY Presentation. Energy Recovery Calculation. Agenda. Energy Recovery Calculation a) Psychrometric Chart b) How to calculate SA Temperature c) How to calculate SA Enthalpy d) Energy recovery calculation e) Cost saving

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Confidential

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  1. Confidential Nakatsugawa Works LOSSNAY Presentation Energy Recovery Calculation

  2. Agenda Energy Recovery Calculation a) Psychrometric Chart b) How to calculate SA Temperature c) How to calculate SA Enthalpy d) Energy recovery calculation e) Cost saving *Refer to Lossnay Technical Manual (Unit) Chapter 2, 3 Energy Recovery Calculation

  3. Psychrometric Chart A chart that shows the properties of humid air. Terminology • Dry Bulb temperature (C) • measured by conventional thermometer • Wet Bulb temperature (C) • measured by thermometer wrapped in a piece of wet gauze and ample air flow • Relative Humidity (%) • the ratio of the water vapor pressure • Absolute Humidity (kg/kg) • the weight of the water vapor • Enthalpy (kJ/kg , kcal/kg) • physical matter has a set heat when it is at a certain temperature and state. • Dew point (C) • The point at when moisture in the air will start to condense into surface liquid If two values are known The other values can be found with Psychrometric chart

  4. Psychrometric Chart Enthalpy ｈ [ｋＪ／ｋｇ] Dew point line φ＝100％ Relative humidity φ[％] Enthalpy ｈ Absolute HumidityＸ　［ｋｇ/ｋｇ（DA)] Absolute HumidityＸ Wet Bulb Tempｔ℃ Dry Bulb Temp -5oC Dew point ｔ” ｔ’ ｔ 45oC Dry Bulb Temp　ｔ　　[oC]

  5. Psychrometric Chart Latent heat h2 Φ2% Enthalpy[ｋＪ／ｋｇ] h Dew point lineφ＝100％ Ｘ2 Absolute Humidity[ｋｇ/ｋｇ] Relative Humidity φ% Sensible heat Ｘ -5oC ｔ ｔ2 45oC Dry Bulb Temp[oC]

  6. 60 50 78.3 kJ/kg 25.7 C 23.3 C 0.018 43 kJ/kg 15.5 C 11.5 C 0.0082 22 32 Psychrometric Chart Example Relative Humidity (%) 80 70 40 100 90 Enthalpy (kcal/kg (DA) Wet Bulb Temperature(C) 0.020 Absolute Humidity (kg/kg (DA)) 0.010 0 10 20 30 40 50 Dry Bulb Temperature (C)

  7. Indoor Outdoor tSA tEA tRA tOA How to calculate SA (supply air) Temperature <Terminology> tSA: Supply air temperature tRA: Return air temperature tOA: Outdoor air temperature tEA: Exhaust air temperature nt: Temperature exchange efficiency Summer condition tSA = tOA - (tOA - tRA) x nt Winter Condition tSA = (tRA - tOA) x nt + tOA

  8. Winter nt = 70% 19oC 25oC 5oC tRA tSA 20oC 14oC tOA 5oC 19oC 25oC How to calculate SA (supply air) Temperature <Example 1 - Winter condition> Room Temp: 25oC Outdoor Temp: 5oC Temperature exchange efficiency: 70% Winter Condition tSA = (tRA - tOA) x nt + tOA = (25 ‐ 5) x 0.7 + 5 = 14 + 5 = 19 [oC]

  9. nt = 80% tOA 8.8oC 11oC tSA tRA 24.2oC 22oC 33oC How to calculate SA (supply air) Temperature <Example 2 - Summer condition> Room Temp: 22oC Outdoor Temp: 33oC Temperature exchange efficiency: 80% Summer 24.2oC 22oC 33oC Summer condition tSA = tOA - (tOA - tRA) x nt = 33 ‐ (33 ‐ 22) x 0.8 = 33 - 8.8 = 24.2 [oC]

  10. How to calculate SA (supply air) Temperature <Test> Please find SA temperature! Room Temp: 20oC Outdoor Temp: Winter 3oC, Summer 35oC Temperature exchange efficiency: 75% Winter Summer ??oC ??oC 20oC 35oC 20oC 3oC Winter Condition tSA = (tRA - tOA) x nt + tOA Summer condition tSA = tOA - (tOA - tRA) x nt Answer is on next page.

  11. How to calculate SA (supply air) Temperature <Test Answer> Room Temp: 20oC Outdoor Temp: Winter 3oC, Summer 35oC Temperature exchange efficiency: 75% Winter Summer 23oC 15.8oC 20oC 35oC 20oC 3oC Winter Condition tSA = (tRA - tOA) x nt + tOA = (20 ‐ 3) x 0.75 + 3 = 12.8 + 3 = 15.8 [oC] Summer condition tSA = tOA - (tOA - tRA) x nt = 35 ‐ (35 ‐ 20) x 0.75 = 35 – 11.25 = 23.8 [oC]

  12. Indoor Outdoor iSA iEA iRA iOA How to calculate SA (supply air) Enthalpy <Terminology> iSA: Supply air enthalpy iRA: Return air enthalpy iOA: Outdoor air enthalpy iEA: Exhaust air enthalpy ni: Enthalpy exchange efficiency Summer condition iSA = iOA - (iOA - iRA) x ni Winter Condition iSA = (iRA - iOA) x ni + iOA The same way of calculating temperature.

  13. Energy recovery calculation [Summer example] Psychrometric Chart Calculate SA temp. tSA = tOA - (tOA - tRA) x nt = 33 - (33 - 26) x 0.76 = 27.7oC Calculate SA enthalpy iSA = iOA - (iOA - iRA) x ni = 84.6 - (84.6 – 52.9) x 0.71 = 62.1 kJ/kg Find SA relative humidity by Psychrometric Chart RHSA = 58%

  14. Supply Air Exhaust Air Sensible ERV General Fan Lossnay D.B. (C) 27.7 27.7 33 A.H. (g/kg) 13.4 20.1 20.1 R.H. (%) 58 86 63 62.1 79.2 84.6 Enthalpy(kJ/kg) Recovered heat (kW) 7.5 1.8 0 OA load (kW) 3.1 8.8 10.6 OA load ratio (%) 29 83 100 Outdoor Air Indoor Air DB: 33 C 20.1g/kg (DA) AH: DB: 26 C 10.5g/kg (DA) AH: RH: 63% 84.6kJ/kg (DA) Enthalpy: RH: 50% 52.9kJ/kg (DA) Enthalpy: Energy recovery calculation [Summer example] Model: LGH-100RX5-E Temp. efficiency: 76% Enthalpy eff. (cooling): 71% Ventilation rate : 1,000m3/h Air Conditioner

  15. Energy recovery calculation [Summer example] Relative Humidity (%) 80 70 60 50 40 100 90 Outdoor air load 100% 71% Enthalpy (kJ/kg (DA) Recovered by Lossnay 29% OA 20.1 17.3 EA 13.4 SA Absolute Humidity (g/kg (DA)) 10.5 10.0 RA 26 33 0 10 20 30 40 50 32 27.7 Dry Bulb Temperature [oC]

  16. Energy recovery calculation [Winter example] Psychrometric Chart Calculate SA temp. tSA = (tRA - tOA) x nt + tOA = (20 - 0) x 0.8 + 0 = 16 oC Calculate SA enthalpy iSA = (iRA - iOA) x ni - iOA = (38.5 - 4.7) x 0.725 + 4.7 = 29.2 kJ/kg Find SA relative humidity by Psychrometric Chart RHSA = 46%

  17. Supply Air Exhaust Air Sensible ERV General Fan Lossnay D.B. (C) 16 16 0 A.H. (g/kg’) 5.2 1.9 1.9 R.H. (%) 46 17 50 29.2 21 4.7 Enthalpy(kJ/kg) Recovered heat (kW) 8.2 5.5 0 OA load (kW) 3.1 5.8 11.3 OA load ratio (%) 27 51 100 Outdoor Air Indoor Air DB: 0 C 1.9g/kg’ AH: DB: 20 C 7.3g/kg’ AH: RH: 50% 4.7kJ/kg Enthalpy: RH: 50% 38.5kJ/kg Enthalpy: Energy recovery calculation [Winter example] Model: LGH-100RX5-E Temp. efficiency: 80% Enthalpy eff. (heating): 72.5% Ventilation rate : 1,000m3/h Heating System

  18. Energy recovery calculation [Winter example] Relative Humidity (%) 80 70 60 50 40 100 90 Enthalpy (kJ/kg (DA) Outdoor air load 100% Absolute Humidity (g/kg (DA)) 27.5% 10.0 72.5% Recovered by Lossnay 7.3 RA EA SA 5.2 4.2 1.9 OA 0 4 10 16 20 30 40 50 Dry Bulb Temperature [oC]

  19. 10.6 11.3 0 0 8.8 1.8 5.8 5.5 3.1 7.5 3.1 8.2 Energy recovery calculation Heat recovery comparison Summer Winter General Fan General Fan Sensible ERV Sensible ERV Recovered cooling load Recovered heat load Lossnay (ERV) Lossnay (ERV) 0 3 6 9 12 0 3 6 9 12 (kw) (kw)

  20. Cost saving Cost saving calculation To be continued

  21. Cost saving Cost saving calculation

  22. 75.3 76.8 0 0 62.5 12.8 39.4 37.4 21.8 53.5 21.3 55.5 Cost saving Cost saving comparison Summer Winter General Fan General Fan Sensible ERV Sensible ERV Cost saving Cost saving Lossnay (ERV) Lossnay (ERV) 0 20 40 60 80 0 20 40 60 80 (x 1000 JPY) (x1000 JPY)

  23. To Be Continued…

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