Air Handler

Large Space Airconditioning
Ductless Air Distribution
Stainless AHU Build
Factory Aircon

System Design

Dove Thermal designs and builds ductless air distribution systems for large space airconditioning. Our ductless aircon systems are designed for Low Cost Climate Control in new and existing distribution warehouses, factories, public buildings and long-term chilled storage sheds. They exploit boundary layer attachment for perfect air distribution throughout very large spaces without recourse to overhead duct systems or equipment. In addition to providing accurate and economical space cooling and refrigeration, our ductless systems achieve significant heating cost reduction during winter months whilst continuing to assure set point control of temperature and humidity. Their effectiveness and value-for-money derive from simplicity in the design and construction of our stainless air handling units, optimized capital and operating costs, and our award-winning record in thermal engineering and project management.

Capability to recover from transient inleakages, and air filtration directed to the capture of FLT tyre dust are specific features, while relative humidities below 70% are necessary for averting damage to cardboard packaging. Connecting areas held at different space conditions can be isolated with air curtains, while infiltration rates must account for loading bay operations and ventilation. Dove Thermal’s factory aircon and warehouse airconditioning ductless systems minimize use of automatic valves and dampers through inverter control of pumps and fans, and the thyristor drive of heating elements. This approach optimizes operating economy, simplifies operation and entails minimal maintenance. Direct expansion systems are preferred for smaller layouts and remote distribution points. Building & racking layout are used to channel air distribution and obviate transmission ductwork in our ductless aircon systems. Illustrated is one of seven sets pulling from the roofspace and delivering air to a facing aisle. Our stainless air handling units are ideal for warehouse airconditioning: they exploit boundary layer attachment of return airflows, and give perfect ductless air distribution in buildings exceeding 50 metres length.

Aircon Load Assessment

Dry heat enters a building through its walls and roof by insolation and convective gain. Insolation is the combined incident radiation from sun, sky and ground; movement of the surrounding ambient air causes transfer of heat to a structure by natural and forced convection. Dove Thermal Engineering has developed unique mathematical models that accurately quantify both processes. These integrate data from a 3D solid model of the building and its specification with a regression of meteorological records for its location. They are also used to predict energy consumption rates for dimensioning power supplies and monthly cost forecasting. Recent work has shown that a standard warehouse shed to current building regulations is viable for most non-frozen storage requirements when using a Dove Thermal system.

Atmospheric moisture is low pressure steam. It is drawn into a building by any difference in partial pressure between its own humid content and that of the outside air. The resultant driving force across boundary layers at the walls and roof determines humid intake to a closed space. Approved Document L2 under Building Regulations 2000 requires that structures enclosing a floor area greater than 1000 sq.m should demonstrate an air permeability rate below 10 cu.m/(h/sq.m) at an applied pressure difference of 50 Pa. Whilst infiltration rate across open doors, vehicle loading docks and ventilation ports can be especially high under through-flow wind-loading, still air conditions during summer also generate considerable humid heat transference to a conditioned space.

Stainless Air Handling Units for Ductless Systems

Dove Thermal has developed unique self-jigging fabrication methods for stainless AHU construction, exploiting state-of-the-art CIM laser profiling to produce precision-built equipment with near off-the-shelf availability. Tongue-and-slot panel location allows a typical accuracy of ± 0.5mm and is applied to our standard range of equipment and custom-built units designed to fit any shape of accommodation space. Our high by-pass ratio air handlers are especially suited to dedicated peak-lopping climate control systems for large space airconditioning. They are a competitive ductless aircon alternative to seasonal hire of rental equipment serving high bay- and wide span buildings for local storage and mid-range warehousing. Thermodynamic dehumidification cools air below its dewpoint, then - conventionally - restores it to set condition using heat recovered from the refrigerant condenser. To remove heat from a conditioned space, then return a proportion to correct relative humidity, is wasteful of power and refrigeration capacity. Although usually practicable only for relatively high capping values, set point condition may be achieved by remixing roofspace air with the cooling coil discharge. This configuration retains the full applied refrigerating effect within the building whilst also providing sufficient recirculation for free field air distribution using downdraught chimneys to draw roofspace air into the air handlers. Ducted networks are needed in large spaces only through the modest air movement capabilities of standard equipment.

Capacity and Workscope

Stainless AHU installations for intermediate contract storage operations • Systems modelling, computational analysis and load programming
Ductless air distribution systems for efficiency and economy • High rate by-pass ratio concept for efficient peak lopping
Warehouse Airconditioning Plant for distribution systems  • Design service for large space airconditioning projects
Factory aircon equipment and installations for manufacturing and services facilities