PRODUCT DIRECT EVAPORATIVE COOLING PAD DATA SHEET

Transcription

1 DIRECT EVAPORATIVE COOLING PAD The only evaporative media with a saturation efficiency over 90% using less than 50% of the volume. Modular Plug & Play design. PRODUCT DATA SHEET

2 DESCRIPTION The OXYVAP Pad has a modular plug and play design including a self-supporting aluminium frame. The evaporative media is based upon our unique and patented water retaining aluminium fins designed for maximum evaporation. The high quality aluminum fins in combination with its unique and patented structure allow for a self-cleaning process during the operating mode, hence preventing the buildup of dirt, mold or calcium, which is typically a problem in competitive evaporative cooling media. Furthermore, thanks to the high water retaining capacity of the fins you don t need to install a droplet eliminator for air speeds up to 3 m/s. The OXYVAP can be applied in a wide variety of applications requiring cooling (residential buildings, air handling units for commercial/industrial buildings, livestock, horticulture) and/or humidification (residential/commercial/industrial buildings, process control). It may also be used to pre-cool the air for a condenser coil in a traditional air conditioner. TECHNOLOGY PRINCIPLE Outdoor air During the cooling season hot intake (outdoor) air flows through the OXYVAP and is cooled down by the adiabatic evaporation process whereby the energy to evaporate the water is retreived from the air itself. Evaporative media and cooling principle Cold Supply air OXYVAP water supply OXYVAP water distribution

3 CONFIGURATION AND DIMENSIONS The OXYVAP is available in the following standard sizes: OXYVAP Finned Finned Frontal finned Air Total Ref. Code Total WxH Width Height Surface speed air flow Mod. 303/301/ mm x 301 mm 276 mm 242 mm 0,067 m 2 2,5 m/s 601 m 3 /h Mod. 303/601/ mm x 601 mm 276 mm 542 mm 0,150 m 2 2,5 m/s m 3 /h Mod. 505/601/ mm x 601 mm 478 mm 542 mm 0,259 m 2 2,5 m/s m 3 /h Mod. 601/601/ mm x 601 mm 574 mm 542 mm 0,311 m 2 2,5 m/s m 3 /h Mod. 303/901/ mm x 901 mm 276 mm 842 mm 0,232 m 2 2,5 m/s m 3 /h Mod. 505/901/ mm x 901 mm 478 mm 842 mm 0,402 m 2 2,5 m/s m 3 /h Mod. 601/901/ mm x 901 mm 574 mm 842 mm 0,483 m 2 2,5 m/s m 3 /h Mod. 892/601/ mm x 601 mm 865 mm 542 mm 0,469 m 2 2,5 m/s m 3 /h Mod. 892/937/ mm x 937 mm 865 mm 878 mm 0,759 m 2 2,5 m/s m 3 /h 36 mm H W D = 96 mm The OXYVAP is easy to mount. The external frame contains slots for screws and bolts on all sides of the heat exchanger.

4 MODULAR CONFIGURATIONS The aluminium OXYVAP frame is self supporting and has been especially designed to put several pads together both horizontally and vertically as shown in the pictures below. The water distribution tube will continue over several pads stacked together horizontally. In case the pads are stacked together vertically, the water supply will be needed for the upper pad only. The water that cascades from above will be redistributed again on the pad below to guarantee a perfect water distribution for the entire finned pack, even on multiple pads. The OXYVAP frame is self-supporting for pad assemblies up to 2000 mm x 2000 mm.

5 OPTIONAL ADDITIONAL FRAME For large pad assemblies with sizes over 2000 mm x 2000 mm, we recommend the use of an additional frame. This solution can be very useful for applications in Datacenters and for pre-cooling the air before a condenser coil in a Chiller. The pads can be clicked individually onto the frame and it is also possible to remove one single pad without having to disassemble the entire structure.

6 PERFOMANCE CURVES The first set of two graphs show the saturation efficiency and pressure drop as a function of frontal air velocity under the Australian Standard AS The superior evaporation efficiency of the patented OXYVAP media is reflected in the high saturation efficiency, even at higher air velocity. The required fan power is minimized by its low pressure drop, maximizing energy efficiency. Third party evaluations under Australian Standard AS (TNO Netherlands and CSIRO Australia) have indicated a saturation efficiency between 89% and 93%. Saturation Efficiency Pressure Drop The second set of two graphs on the next page illustrate the difference in performance under AS between OXYVAP and a common paper deck evaporative media for a standardized frontal surface area of one square meter and various thicknesses.

7 Saturation Efficiency OXYVAP vs. paper deck Pressure Drop OXYVAP vs. paper deck Compared to competitive evaporative media OXYVAP based systems typically require less than 50% of the volume of evaporative media to offer the same cooling capacity or alternatively deliver more than double the cooling capacity at equal volume. WATER QUALITY REQUIREMENTS The OXYVAP can be operated with regular tab water. In general, if the water is potable, it can be used for the OXYVAP. A long-term supply of water having an electrical conductivity higher than 1000 µs/cm (corresponding to about 700 mg/l of Total Dissolved Solids or TDS) is not recommended because of the risk of scale formation, which may reduce cooling performance and lifetime. Despite the lack of an unambiguous definition, 1000 µs/cm is often considered the transition between potable water and brackish water. Purified water (e.g. distilled or demineralized) should not be used because of the risk of corrosion.

8 WATER SUPPLY METHOD The water can either be supplied in a continuously flow or in an intermittent flow, depending on whether a simpler or a less water consuming method is preferred. Continuous flow (less water consuming method): Supplying a continuous flow of water to the pad is a good method of keeping the pad material entirely wet, while constantly removing pollutants and minimizing scale formation. To achieve this, the pad is supplied with significantly more water than is actually being evaporated, typically by a factor of at least 12. A water flow of about 360 L/h per meter width shown in the table on page 3 is recommended. To avoid unnecessary waste of water, the water supply system should be equipped with a water reservoir to reuse the excess water that has not been evaporated. Water lost by evaporation should be replaced by tap water. Long-term use requires either a continuous bleed-off or, preferably, a periodic sump dump to keep the water reservoir clean. The bleed-off or dump should be able to maintain the electrical conductivity in the water reservoir below 1000 µs/cm. Although the required bleed-off rate depends on factors such as tap water quality (electrical conductivity, hardness, ph value) and water reservoir volume, tests [1] have shown that a value in the order of 15% seems to be sufficient in many cases. Long-term testing also requires an ozone generator or similar device to prevent growth of algae and moulds in the water reservoir. Intermittent flow (simpler method to implement): Supplying an intermittent flow of water to the pad is a good alternative when a simple water supply system is desired, in which excess water is not being reused. Neither does it require any form of water quality management system. It is preferred to supply water to the pad by means of an alternating cycle in which the water flow is switched on for 2 seconds and switched off for 8 seconds, such that the total water flow equals about 64 L/h per meter width shown in the table on page 3. With this method the total water consumption is equal to twice the water quantity that evaporates. To make performance calculations or to calculate the quantity of evaporated water, you can use our Selector. This is an online tool that allows you to make calculations for direct or indirect evaporative cooling, dew point cooling or air humidification. To access the Selector, please visit for a free registration. [1] OXYCOM FRESH AIR BV (2012). Analysis of Water Quality Behaviour in a Direct Evaporative Cooler. Document ID: XRD-F TECHNOLOGY VALIDATIONS AND RECOGNITION TNO Evaluation Report OXYVAP Pad CSIRO evaluation Report OXYVAP Pad VIPAC evaluation Report OXYVAP based In Roof Direct Evaporative Cooler Concept OXYCOM FRESH AIR BV Heesweg 37, 8102 HJ Raalte P.O. Box 212, 8100 AE Raalte, The Netherlands Phone Fax E info@oxy-com.com