YORK Modular Integrated Terminals - aireclima.com

1 FORM (899) york ModularIntegrated TerminalsConvection Enhanced VentilationTECHNICAL MANUAL2 york INTERNATIONALThis page intentionally left INTERNATIONAL3 FORM About This Manual ..42. Convection Enhanced Ventilation (CEV) Comfort with the MIT ..64. york MIT terminal Description ..85. Energy Indoor Air Quality ..127. Issues That Affect Load Calculations .. Location of cooling loads in the Return Air Thermal decay (loss of supply air cooling ability) Thermal increase (decrease in return air temperature) Thermal storage due to building Load Stratification and ceiling height8.

2 Psychrometric Considerations ..169. Choosing the Best Locations for the MIT Terminals ..1910. Plenum Based Air Distribution .. Moisture and Locating Floor Air Supply Plenum Air Velocity and Air Pressure Drop11. Ducted Air Distribution ..2112. Fire, Smoke, and Other Code Issues ..2415. Air Handling System Features .. Plug (plenum) Sidestream Direct Expansion Applications16. System Controls and Air Handling Unit Operational Sequence .. Discharge air control full economizer Discharge air control no economizer Cooling coil discharge air control no economizer Discharge air reset Plenum and duct distribution Supply air drybulb temperature Space pressure control17.

3 Applications .. Occupancy Control and Other Cost System Choice Issues18. Comparison of Additional of Contents4 york INTERNATIONALYORK is developing new products that are intended tooffer unique and cost effective opportunities for solvingmany of the commonplace problems associated with tra-ditional commercial air-conditioning systems. One excit-ing new product is the Modular Integrated terminal (MIT)that is used for the floor up supply of conditioned up systems are not new but they have never beenwidely used in the United States.

4 These upside down airside systems offer the potential to solve energy andindoor air quality problems better than conventional sys-tems. The new york MIT is an enhancement or secondgeneration product that resolves many limitations of pre-vious products while adding features needed for the alternative that has been called displacement effectventilation has also been used. With this concept, sup-ply air, not as cold and at a higher volume , is introducedvery slowly at floor level and allowed to rise upwards as itwarms and becomes buoyant. The design objective is to displace the room air, thus carrying heat and air pollut-ants more directly to the return air inlets, rather than mix-ing them in the room and influencing the room Traditional Overhead System ProblemLD04655 Displacement ConceptThis manual provides technical description of this newtechnology with practical guidelines and recommenda-tions for using york products.

5 It is intended to identifydifferences between this air delivery system and the tra-ditional well-mixed, ceiling based systems. Of particularinterest is the use of floor plenums to distribute air. Thismethod of air distribution is cost effective while providingflexibility beyond any ductwork based system. Manyengineering concepts have to be adjusted for this new airdelivery method and the information included offers in-sight into developing final design solutions. It must beemphasized that this manual is only a guide and an in-troduction of the complex issues involved in applying thistechnology.

6 Final design parameters and equipment se-lection should be carefully reviewed by experienced engi-neers familiar with this About This Manual2. Convection Enhanced VentilationMost commercial air-conditioning systems use the ceil-ing or a high wall location as the supply point for thecooling air. The thought is that cool air drops, and thislocation is therefore best. Mixing the supply air (whichmust be quite cold for cooling) with the room air as quicklyand completely as possible avoids drafts and tempera-ture variations everywhere in the room.

7 Thus, this tradi-tional system is known as a well-mixed INTERNATIONAL5 FORM International now proposes a hybrid system, offer-ing advantages of both the well-mixed and the displace-ment types of air distribution, while at the same timeovercoming their is named Convection Enhanced Ventilation, or simply CEV, and it has additional features that make it supe-rior to both previous approaches. It uses a completelynew variable air volume distribution device that is installedin raised flooring technology supplies the cool air vertically at floorlevel like displacement effect ventilation, but at a con-stant velocity.

8 The design objective is to mix supply airwith room air only up to head height. Above this level,stratification is allowed to are the benefits of york s CEV technology?1. Improved comfort Drafts are avoided and comfortable temperatures areintended to occur only where the people are, not wherethey aren't (as happens with the well-mixed airdistribution systems). Each of the new Terminals can be controlled by itsown thermostat, responding to the occupant'stemperature Reduced energy consumption. CEV plenum distribution systems require less staticpressure (fan energy is reduced) similar to displacement air distribution Enhanced Ventilation CEV is truly variable air volume (unlike displacement air distribution systems).

9 With a warmer supply air temperature, fewer hoursof mechanical refrigeration operation are necessary. Less outside air (usually requiring dehumidification)is required for the same ventilation Better indoor air quality Occupants have first benefit of cooled, filtered, andfresh air supply. More effective contaminant dilution in the occupiedpart of the room due to a unique filtration approach. A dry (60-65 F [ C] 65%-80% ) ratherthan a moist (55 F [ C] /100% ) air Can Feel The Better IAQ With CEVLD04656 Operating Cost With CEV6 york INTERNATIONAL4.

10 More flexibility The air Terminals can be relocated quickly and easily,changing from master units thermostaticallycontrolling temperatures to slaves (and vice versa).5. Lower installed costs When compared to quality conventional systemsoffering only some of the CEV system's first under floor air-conditioning systems performedbest at full-load, or nearly full-load, conditions. This wasoften acceptable, because they were used in areas withlittle variation in cooling load. However, for areas whereloads did vary, such as perimeter zones during interme-diate seasons, when transmission and/or solar loads wereless than design conditions, or in other spaces wherepeople and lighting loads could decrease, over-coolingcould result is a lower comfort level than would occur withconventional overhead systems.