Design, implementation and evaluation of solar-powered on-farm dew collection system for arid regions

Thesis Abstract

In arid and semi-arid farming systems, water scarcity constrains crop production and livelihoods, making reliable water provisioning and efficient use critical. This study addresses the gap in sustainable dew-based irrigation solutions by designing, implementing, and evaluating a solar-powered on-farm dew collection system that harvests micro-scale condensation on farm surfaces to supplement prevailing water supplies. The aim is to quantify dew yield potential, assess system performance under diverse meteorological conditions, and evaluate impacts on crop water use efficiency and farm profitability. Specific objectives include (i) characterizing dew formation dynamics and estimating achievable daily dew yields across representative microclimates in arid regions; (ii) developing a modular, low-cost solar-assisted dew condensers integrated with passive radiative cooling surfaces and mesh collectors; (iii) implementing the system on ten farm plots of 0.2 hectares each, distributed across three villages, to capture spatial variability; (iv) evaluating system reliability, energy balance, and dew-to-use conversion efficiency over two dew seasons using on-site data acquisition; (v) assessing agronomic and economic outcomes such as crop transpiration reductions, irrigation water savings, and net farm income changes; and (vi) proposing a scalable deployment framework aligned with local extension and policy contexts. The methodology adopts a mixed-methods design anchored in the positivist paradigm for quantitative measurement and complemented by a pragmatic approach to interpretation. The population consists of arid-region farmers and their representative microclimates; a stratified random sampling yields 60 measurement days per site, with continuous data collection over 24 months. Data collection instruments include automated dew collectors with calibrated hygrometers, pyranometers, soil moisture probes (10 cm and 30 cm depths), flow meters, weather stations, and farm economic records. Instrument validity is established through calibration against standard references, and reliability is evaluated via test-retest procedures and inter-instrument comparisons, yielding a Cronbach’s alpha above 0.85 for survey items and an R2 exceeding 0.90 for sensor concordance. Data analysis employs descriptive statistics and time-series decomposition to characterize dew formation patterns, multiple regression to model dew yield as a function of ambient temperature, relative humidity, and surface emissivity, and ANOVA to compare performance across sites. A hydrological balance framework estimates water savings and irrigation requirements, while a simple partial budgeting model evaluates economic viability. The study also analyzes user acceptance through thematic analysis of farmer interviews, guided by the Technology Acceptance Model to identify adoption determinants. Theoretical underpinnings draw on the principles of energy-water nexus and surface radiation thermodynamics, with explicit reference to the Theory of Planned Behavior to interpret adoption outcomes. Expected findings indicate that solar-assisted dew collectors can achieve mean daily dew yields of 0.5–1.2 L m?2 under favorable humidity and clear-sky conditions, with higher yields on cooler nights and surfaces with high emissivity. System reliability is anticipated to be adequate in most months, with overall water savings translating into 8–15% reductions in supplemental irrigation requirements and 5–10% improvements in crop water use efficiency for drought-sensitive crops such as wheat and chickpea. Economic analysis is expected to reveal a positive net present value within a three-year horizon at modest capital costs (USD 150–250 per m2 of collector area) and low maintenance, supported by feed-in or off-take incentives. The study contributes to knowledge by providing empirical evidence on the feasibility, performance, and economic viability of on-farm dew collection integrated with solar energy in arid agrarian systems, identifying design parameters that optimize condensation capture, and offering a deployment blueprint aligned with rural livelihoods and policy frameworks. The main conclusion anticipates that solar-powered dew collection constitutes a viable supplementary water source to improve resilience in arid farming, particularly when combined with crop choice, soil moisture management, and appropriate scale-up strategies; recommendations include standardizing collector modules, developing farmer-friendly maintenance protocols, and integrating dew collection with local water governance and extension services to maximize adoption and impact.