Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Citations (Scopus)

Abstract

Water availability is a common concern in semi-arid regions, such as Southern Arizona, USA, where more greenhouses are operating due to high solar radiation. Hydroponic greenhouse crop production greatly reduces irrigation water use; however, there is currently no information demonstrating water use of an evaporative cooling system. This project investigated water use by a pad and fan (P&F) cooling system under semi-arid climate conditions. Data were collected for two physically identical, side-by-side, double-layer polyethylene film-covered arched-roof greenhouses (28 m x 9.8 m x 6.3 m) during summer conditions (38.5°C, 15% RH, 845 W m-2). One greenhouse had mature tomato plants (2.3 plants m-2) and the other had no plants. Water use was primarily affected by air exchange rate. The average water use by the P&F system was 0.145, 0.182, 0.265, 0.325, and 0.387 g m-2 s -1 for greenhouse air exchange rates of 0.017, 0.037, 0.051, 0.067, and 0.079 m3 m-2 s-1, respectively. In the empty greenhouse, the lowest ventilation rate produced the highest average greenhouse air temperature (Tin=33.8°C) and lowest RH (40%). Tin and RH were nearly equal for the three highest air exchange rates. In the greenhouse with plants, the lowest ventilation rate produced the highest Tin (31.1°C) but also the highest RH (69.4%). In general, RH decreased with increasing air exchange rate and the minimum Tin of 27.6°C (RH: 52%) was achieved at the middle air exchange rate (0.051 m3 m-2 s-1). It is believed that the lower cooling efficiency of the P&F system at higher ventilation rates caused a reduction in cooling. However, the lower ventilation rates limited air exchange and effectively reduced cooling. If a higher pad cooling efficiency could be maintained at high ventilation rates, a cooler air temperature and higher relative humidity may be achieved, though water use would increase. Finally, when the air exchange rate was controlled to maintain the GH at 24°C/18°C during day and night, water use by the P&F cooling system (14.8 L m-2 day-1) was greater than the tomato irrigation system (8.9 L m-2 day-1) assuming 100% drainage recovery, which is typical for many high-technology greenhouse facilities.

Original languageEnglish (US)
Title of host publicationActa Horticulturae
Pages409-416
Number of pages8
Volume719
StatePublished - Sep 2006

Publication series

NameActa Horticulturae
Volume719
ISSN (Print)05677572

Fingerprint

fans (equipment)
semiarid zones
cooling
greenhouses
tin
air
cooling systems
water
air temperature
tomatoes
polyethylene film
irrigation systems
coolers
hydroponics
arid zones
irrigation water
crop production
relative humidity
drainage
solar radiation

Keywords

  • Cooling efficiency
  • Hydroponics
  • Single-span greenhouse
  • Ventilation rate

ASJC Scopus subject areas

  • Horticulture

Cite this

Sabeh, N. C., Giacomelli, G. A., & Kubota, C. (2006). Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate. In Acta Horticulturae (Vol. 719, pp. 409-416). (Acta Horticulturae; Vol. 719).

Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate. / Sabeh, N. C.; Giacomelli, Gene A; Kubota, Chieri.

Acta Horticulturae. Vol. 719 2006. p. 409-416 (Acta Horticulturae; Vol. 719).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Sabeh, NC, Giacomelli, GA & Kubota, C 2006, Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate. in Acta Horticulturae. vol. 719, Acta Horticulturae, vol. 719, pp. 409-416.
Sabeh NC, Giacomelli GA, Kubota C. Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate. In Acta Horticulturae. Vol. 719. 2006. p. 409-416. (Acta Horticulturae).
Sabeh, N. C. ; Giacomelli, Gene A ; Kubota, Chieri. / Water use for pad and fan evaporative cooling of a greenhouse in a semi-arid climate. Acta Horticulturae. Vol. 719 2006. pp. 409-416 (Acta Horticulturae).
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