Energy Saving Potential of a Thermoelectric Heat Pump-Assisted Liquid Desiccant System in a Dedicated Outdoor Air System
Abstract
:1. Introduction
2. System Overview
2.1. A THP-Assisted Liquid Desiccant (THPLD) System
2.2. THPLD-Based Dedicated Outdoor Air System (DOAS)
3. Research Methodology
3.1. Building Information
3.2. System Simulation Overview
3.3. Liquid Desiccant Unit
3.4. Standard THP Model
3.5. Membrane Enthalpy Exchanger
3.6. Chiller Model
3.7. Ceiling Radiant Cooling Panel Model
3.8. Fan and Pump
4. Results
4.1. Design of the THP for the LD System
4.2. CRCP Design of System Cases
4.3. Operating Energy Consumption in the Cooling Season
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
Nomenclature
Apex angle (°) | |
Seebeck coefficient (V/K) | |
Specific heat (kj/kg·°C) | |
Diffusivity of water vapor in air (m2/s) | |
Hydraulic diameter (m) | |
Room position index | |
Height (m) | |
Enthalpy (kj/kg) | |
Heat transfer coefficient (W/m2·°C) | |
Mass transfer coefficient (W/m2·°C) | |
Electric current (A) | |
Thermal conductance (W/K) | |
Conduction heat transfer coefficient of air (W/m·K) | |
Panel thermal conductivity (W/m·°C) | |
Leg length (m) | |
Mass flow rate (kg/s) | |
Nusselt number | |
NTU | Number of transfer units |
Density (kg/m3) | |
Electrical resistivity of the TEM (·m) | |
Power (W) | |
Heat flux (kw) | |
Electrical resistance () | |
Thermal contact resistance (K/W) | |
Leg section area (m2) | |
Temperature (°C) | |
Diffuser discharge velocity (m/s) | |
Diffuser width (m) | |
Humidity ratio (kg/kg) | |
Concentration | |
Height of the control volume (m) | |
Thermal conductivity of the TEM (W/m·K) | |
Effectiveness (%) | |
Tube spacing (m) | |
Ratio of the total number of transfer units for moisture to that for sensible heat | |
Panel thickness (m) |
Abbreviations
AC | Air conditioning |
CAPFT | Cooling capacity function of the temperature curve |
COP | Coefficient of performance |
CRCP | Ceiling radiant cooling panel |
DOAS | Dedicated outdoor air system |
DPT | Dew point temperature |
EES | Engineering equation solver |
EIRFT | Energy input to the cooling output ratio function of the temperature curve |
EIRFPLR | Energy input to the cooling output ratio function of the part load ratio curve |
HVAC | Heating ventilating and air conditioning |
LD | Liquid desiccant |
MEE | Membrane enthalpy exchanger |
OA | Outdoor air |
PLR | Part load ratio |
RSHF | Room sensible heat factor |
SA | Supply air |
TEM | Thermoelectric module |
THP | Thermoelectric heat pump |
TRNSYS | Transient systems simulation |
Greek Symbols
Subscripts | |
Air | |
Absorber | |
Cold side | |
Chilled water | |
Chiller | |
Condenser | |
Entering | |
Hot side | |
Leaving | |
Latent | |
max | Maximum |
min | Minimum |
Plate | |
Primary | |
Return air | |
Regenerator | |
Reference | |
Solution | |
Saturation | |
Secondary | |
Sensible | |
Vapor | |
Water |
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Location | Seoul, Republic of Korea | ||||
---|---|---|---|---|---|
Floor area | Office area | 42 m2 | |||
U-value | Exterior wall | 0.511 W/m2K | |||
Roof | 0.316 W/m2K | ||||
Window to wall ratio | 0.5 | ||||
RSHF | 0.97 | 0.9 | 0.8 | 0.7 | |
Ventilation rate | 84 m3/h | 168 m3/h | 378 m3/h | 546 m3/h | |
Lighting density | 13 W/m2 | ||||
Infiltration | 0.3 air changes per hour (ACH) | ||||
Schedule | 07:00–22:00, five days a week | ||||
Indoor air condition (Summer) | Dry-bulb temperature (DBT): 26 °C, Relative humidity (RH): 50% | ||||
Peak sensible cooling load | 4.5 kW | ||||
Peak latent cooling load | 0.2 kW | 0.5 kW | 1.1 kW | 1.9 kW |
Thermal Conductivity | |
Electrical Resistivity | |
Seebeck Coefficient |
Curves | ||||||
---|---|---|---|---|---|---|
CAPFT | 0.958546443 | 0.035168695 | 0.000124662 | −0.00274551 | −0.00005000 | −0.00017234 |
EIRFT | 0.732700123 | −0.00834360 | 0.000638530 | −0.00303753 | 0.000484952 | −0.00083584 |
EIRFPLR | 0.070862846 | 0.002787560 | −0.00000891 | 0.230973399 | 1.250442176 | −0.00216102 |
–66.40919 | –827.67671 | 38798.58774 | 0.33094 | –9.60442 | 16.76649 |
81.44688 | 13.52746 | 2.08691 | 60209.13462 | 0.68300 | 31.74440 |
–36.53724 | –164.59549 | –2216.93209 | 2220.82332 | –0.023188 | 0.024267 |
- | - | ||||
0.12427 | –0.67052 | –3.32718 | 6.69694 | - | - |
Nomenclature | Component | Head Loss |
---|---|---|
Solution pumps for the absorber and regenerator | 0.4 m each at 1.1 m3/h | |
Chilled water for the cooling coil | 0.3 m |
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Kim, M.-H.; Park, J.-Y.; Jeong, J.-W. Energy Saving Potential of a Thermoelectric Heat Pump-Assisted Liquid Desiccant System in a Dedicated Outdoor Air System. Energies 2017, 10, 1306. https://doi.org/10.3390/en10091306
Kim M-H, Park J-Y, Jeong J-W. Energy Saving Potential of a Thermoelectric Heat Pump-Assisted Liquid Desiccant System in a Dedicated Outdoor Air System. Energies. 2017; 10(9):1306. https://doi.org/10.3390/en10091306
Chicago/Turabian StyleKim, Min-Hwi, Joon-Young Park, and Jae-Weon Jeong. 2017. "Energy Saving Potential of a Thermoelectric Heat Pump-Assisted Liquid Desiccant System in a Dedicated Outdoor Air System" Energies 10, no. 9: 1306. https://doi.org/10.3390/en10091306