downdraught air handling unit

Large Space Airconditioning
Ductless Air Distribution
Stainless AHU Build
Factory Aircon

Large Space Airconditioning Design

Dove Thermal designs and builds ductless aircon systems 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 without recourse to overhead duct systems or equipment. In addition to providing accurate and economical large space airconditioning our 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 steel 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, air filtration for the capture of FLT tyre dust, and assured levels of relative humidity below 70% for protection of cardboard packaging are specific features. Our ductless aircon systems for factory and warehouse airconditioning 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. While direct expansion air handling units are preferred for smaller layouts and remote distribution points, larger installations may circulate heat transfer fluid through local air handlers supplied by a central chiller installation.

Building Layout

Building & racking layout are used to channel air distribution and obviate transmission ductwork. Our stainless air handling units are ideal for warehouse airconditioning: they exploit boundary layer attachment of return airflows for ductless air distribution throughout buildings exceeding 50 metres length. Illustrated is one of seven warehouse aircon units pulling from the roofspace of a portal-frame shed, and delivering its conditioned discharge into a facing aisle. Operating on a similar basis, Dove Thermal’s stainless steel factory airconditioning units are designed to complement state-of-the-art manufacturing and services environments.

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 warehouse aircon power supply sizing and monthly cost forecasting. Recent work has shown that a standard steel-framed building to current building regulations is viable for most chilled 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 Factory Airconditioning and Large Space Aircon 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 stainless air handling 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 factory aircon projects. They are a competitive ductless alternative to seasonal hire of rental equipment serving high bay, 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. Removing heat from a conditioned space, then returning a significant proportion of it to correct relative humidity, is wasteful of power and refrigeration capacity. Depending upon capping temperature, set point conditions may be maintained by remixing unconditioned warm air with the cooling coil discharge. A high by-pass ratio allows the full applied refrigerating effect to be retained inside the building, whilst also providing sufficient recirculation for free field distribution through downdraught chimneys. Ducted networks are needed for large space aircon only through the modest air movement capabilities of standard equipment.

Capacity and Workscope:

Stainless AHU installations for ductless aircon contract storage operations

Systems modelling, computational analysis and load programming

High rate by-pass ratio concept for efficient peak lopping

Factory airconditioning systems for manufacturing plants

Ductless air distribution for large space aircon systems

Warehouse Aircon Plant for ductless installations

Design service for factory aircon projects

Dove Thermal Engineering Limited, Uttoxeter, ST14 8QX

Telephone: 01889 569933