Executive Summary
This paper presents a high-level technical and commercial investigation into a novel solar-powered atmospheric water generation (AWG) system designed for remote, off-grid agricultural applications in Australia. Addressing the critical issue of water scarcity in inland regions like Gunnedah, New South Wales, where rainfall variability, drought cycles, and rising water delivery costs threaten agricultural productivity. The proposed system uniquely employs a CO2-based vapor compression refrigeration (VCR) cycle as its core technology. While CO2 (R-744) is an established refrigerant in commercial refrigeration, its application in AWG is theoretical and believed to be the first of its kind. This investigation sought to determine if such a system could offer a viable, low-emissions, and energy-efficient solution for potable water generation from air.
The analysis, based on Gunnedah’s climate data, modeled water production capacities for 100 L/day for small-scale needs and as a proof of concept. Key technical findings indicate that to produce 100 L/day, approximately 2,284 m3 of air per hour would need to be processed, requiring an estimated electrical input of 11 kW, or 49.5 kWh/day, assuming a Coefficient of Performance (COP) of 2.0.
A preliminary financial analysis, benchmarking against the cost of trucked water, projects a negative Net Present Value (NPV) of -$61,292.80 over a 20-year lifespan for a 100 L/day system with an estimated capital cost of $57,900. Despite this, the system offers substantial non-monetary benefits, including enhanced water security and resilience against drought, reduced reliance on carbon-intensive trucking, and alignment with environmental and sustainability goals.
Significant risks include the system’s theoretical nature and lack of commercial availability, the complexity of high-pressure transcritical CO2 operation, and the need for specialised components and maintenance. Recommendations for future steps include;
- exploring funding opportunities to improve commercial viability and support its development as a critical resilience infrastructure investment.
- scale sensitivity analysis,
- evaluating performance in varying ambient conditions,
- detailed costing, and
Table of Contents
Executive Summary
1. Introduction / Background 8
3. Technology Overview 9
3.1 Current Technology Maturity of the CO2 AWG System 9
3.1 Introduction to Atmospheric Water Generation (AWG) 9
3.2 Atmospheric Conditions and Water Yield 9
3.3 Active AWG Systems 11
a. Vapor Compression Refrigeration (VCR) 11
b. Thermoelectric Cooling (TEC) 12
3.4 Passive AWG Systems 12
a. Fog Nets 12
b. Absorbent-Based Systems (Desiccants) 13
c. Radiative Dew Collectors 14
d. Dew Water Harvesting Systems 15
3.5 Hybrid Approaches 15
4. Technical Assessment 17
4.1 Understanding the Transcritical CO2 Cycle (with P-h Diagram) 18
4.2 Results 20
Assumptions 20
Daily Throughput and Air Volume Required 20
Heat Removed per Hour 21
Estimated Electrical Input 21
5. Economic & Commercial Feasibility 22
5.1. Current Market Options 22
5.2 Comparison with Alternative Water Supply Technologies 23
5.3 Preliminary Financial Analysis 25
Assumptions 25
Outcome 25
5.4 Discussion 25
Resilience & Water Security 25
Environmental & Strategic Benefits 25
Scalability & Innovation 26
6. Risks & Considerations 27
Technology Availability and Maturity 27
System Design and Operational Complexity 27
Water Quality and Treatment 27
Economic Viability 27
Environmental and Climatic Sensitivity 28
Technical Integration and Maintenance 28
7. Recommendations & Next Steps 29
1. Scale Sensitivity Analysis 29
2. System Performance at Higher Ambient Conditions 29
Detailed Costing and Procurement Review 29
Power Supply Scenario Planning 29
Regulatory and Compliance Review 29
Site-Specific Feasibility 29
Stakeholder Engagement and Funding Opportunities 29
Hybrid system 29
7. Conclusion 30
Appendix 1 31
Electrical Demand Calculation 31
8. References