A masterclass in low energy ventilation for classrooms

Air quality in classrooms has a major bearing on the academic performance and productivity of occupants and with air pollution levels continuing to rise in the UK, especially in cities, it has become increasingly important that these issues are addressed.

Dunham-Bush’s Commercial Manager, John Tarling, focuses on indoor air quality.

Released by the government last year, BB101: ‘Ventilation, thermal comfort and indoor air quality 2018’ has been instrumental in the most significant changes in ventilation design, regulation and guidance in schools since 2006. Working in parallel with BB93: ‘Acoustic designs for schools, performance standards (2015),’ it gives a detailed holistic approach to the internal environment in schools with the emphasis very much on energy efficiency.

BB101 guidelines on ventilation include standards for all spaces within a school or college and new guidance for science labs and other practical areas.

All ventilation systems must have the capability to operate in typical UK weather conditions, including high winds and rain. Final ventilation designs will depend on the following key factors:

• Building location
• Type of construction
• Site ambient noise levels
• Local air quality / levels of pollution
• Amount of glazing / solar gain
• Patterns / type of use

Preventing overheating in summer is a major factor in school design and CIBSE TM52 ‘Limits of Thermal Comfort: Avoiding Overheating’ is intended to correctly model schools. Good ventilation combined with an effective night cooling strategy is recommended, especially where appropriate building thermal mass is present, to maintain acceptable internal room temperatures during summer months.

The Classmaster heat recovery ventilation unit has been developed specifically for classrooms and as with all the VHR range of units now available from Dunham-Bush, fully complies with the very latest BB101 and BB93 guidelines. With nine chassis sizes and airflows ranging from 50 to 600 l/s, Classmaster delivers the very highest standards of air quality to meet every classroom requirement.

Key features include a patented variable air mass flow heat exchanger, which maintains thermal efficiency at both 100% and 50% airflow levels by cleverly keeping turbulent velocity airflow across the heat exchanger. This is not possible with conventional heat exchangers, as airflow goes into a laminar flow with little or no exchange of thermal energy.

The unique configuration of low resistance heat exchangers, used in conjunction with 100,000-hour long life, low energy EC fans, delivers minimal sound levels and an impressive heat reclaim efficiency up to 89%.

With a low-profile height of only 300mm, Classmaster can be installed within a ceiling void or surface mounted. Space heating options are available across the complete range of Classmaster and VHR heat recovery and ventilation units, with a comprehensive range of frost and heating coils pre-installed in insulated casings and matched flanges to fit directly onto heat recovery units.

Versatile control options

The factory fitted Eco-Pro 3 Controller offers a plug and play capability and is ideal where stand-alone control is required. Units can be activated either via volt free contact (VFC) from a time switch or BMS (enable / disable signal). The controller can   give fault outputs to the Eco-Fault panel or BMS panel.

The factory fitted Trend IQ422 Controller offers individual and adjustable fan speeds on trickle and boost settings in all modes of operation. Frost protection, automatic summer by-pass and night time cooling options are standard.

Full integration with BMS BACnet or Trend systems for energy management and monitoring is available with filter monitoring via built in DP switches.

The result of several years research and development, these innovative products offer a proven solution to the requirements of BB101: 2018.

The Smart-Vector range of fresh air fan convectors offer further innovative options to the client, ensuring recommended indoor air qualities (IAQ) are achieved when project budgets are limited or building layout is restrictive. Smart-Vector provide demand-led tempered fresh air and heating using a stand-alone controller with local setpoint adjustment.

There are five models in the Smart-Vector range: floor standing front outlet model SV19; floor standing top outlet model SV88; high wall model SV53; ceiling mounted SV80 and a floor standing ducted tall cabinet front outlet model SV22.

The wall mounted digital controllers provide modulating outputs to control the fan, damper and control valve, enabling minimum use of energy, low noise level and low CO2 levels.

The Smart-Vent controller is used in conjunction with the Smart-Vector controllers and allows Building Managers to enable free cooling. Smart-Vent is specifically designed for projects that require up to 32 rooms to be controlled independently, where a dedicated BMS system is not being installed.

www.dunham-bush.co.uk