LAUSR

Abstract A low-capacity (15.5-L) evaporative cooler, utilizing zeolite as an adsorbent, for saving smallholder dairy farmers’ evening milk, was not well received due several factors, addressed in the second generation higher capacity (>50 L) design. Like the first generation the new design uses zeolite and is powered by biogas. The first development step was to establish a protocol for testing commercially available zeolites to determine zeolite suitability for use in the design and to characterize the performance of a zeolite biogas-powered regenerator. Using an in-house developed protocol, zeolite beads of diameters 2.5–5 mm were tested and we found that 10 angstrom (A) zeolites have a higher water adsorption capacity (6–7%) in comparison to 3 A zeolite beads, suggesting that larger pore zeolites provide higher cooling capacity. However, large pore zeolite beads showed up to 18 times variance in repeat water adsorption compared to 3 A zeolite, indicating that zeolite of small pores may provide more cooling cycles. Our biogas powered regenerator achieved and maintained the regeneration temperature of 200 °C when tested with both propane and biogas. This result affirms that our system can be operated on the farm using biogas as the energy source.