Abstract
We present dynamic, hour-by-hour modelling of a multi-stage nanofiltration regeneration system for liquid desiccant air-conditioning (NF-LDAC) of horticultural greenhouses in 17 locations covering four climate types. Four technologies are compared: fan ventilation, evaporative cooling (EvapC), conventional air-conditioning (AC), and NF-LDAC. The comparison is based on acceptable conditions for cultivation and coefficient of performance (COP). On average, fan ventilation and EvapC achieve acceptable conditions for 2 months per year, compared to 5.4 and 10.5 months for AC and NF-LDAC respectively. The highest COP value of 7.6 for NF-LDAC is reached at Colombo (Sri Lanka), followed by 5.3 at Mecca (Saudi Arabia). The permeate of the multi-stage regenerator can be recycled for irrigation, providing water savings. The highest water saving of 63% is at Mecca. These results are inferior but more realistic than those from an earlier idealised and steady-state model, which predicted a COP of 12.4 and water savings of 100% at Mecca. Nevertheless, in hot desert climates, NF-LDAC maintains acceptable conditions for year-round cultivation and saves water that is scarce in such climates. Future advances in nanofiltration membrane fabrication could increase the COP of NF-LDAC to 12.1 at Colombo and 7.4 at Mecca.
| Original language | English |
|---|---|
| Article number | 122495 |
| Number of pages | 13 |
| Journal | Applied Thermal Engineering |
| Volume | 242 |
| Early online date | 17 Jan 2024 |
| DOIs | |
| Publication status | Published - 1 Apr 2024 |
Bibliographical note
Acknowledgments:P. Pasqualin acknowledges funding from the School of Engineering, University of Birmingham, UK. The authors thankfully acknowledge suggestions and guidance by Ryan Lefers of Red Sea Farms during the early stages of this project.
Keywords
- Liquid desiccant air-conditioning
- Multi-stage membrane regeneration
- Greenhouse cooling
- Coefficient of performance