Curtain up on savings
With 2018 temperatures dipping to a stark -15oC and peaking at 35.5oC, building owners need to ensure they have sophisticated measures in place to manage the comfort of their employees, especially as there is currently no upper temperature limit for workers.
Employers have a duty of care to provide a comfortable working environment for employees. Providing the best experiences for occupants is a top priority for property owners and building managers.
Heating is a necessity and therefore very important that it is done right. Clients need to determine exactly what kind of system they wish to employ. Options might include a warm air heating system; a radiant ‘spot’ heating system; or a full radiant heating system. Each method has its own benefits and constraints, which depend on the building style and proposed use.
Most buildings that operate on a closed-door policy tend to be ideal for a warm unit heater system which can be conveniently positioned to ensure an even distribution of heat throughout the space. In this type of project, gas fired suspended warm air unit heaters which will suit almost every warm air application. And when used in conjunction with destratification, fans will help ensure that the whole space is heated and at the same time reduce energy costs by re-using any wasted heat that has gathered within the roof space and returning it to low level.
Door policy
Where buildings operate an opendoor policy, have poorly insulated buildings or only want to heat a small part of a larger area, then a radiant heating system is more suitable. Radiant tube heaters focus heat on specific areas and do not heat the air, therefore avoiding heat being wasted as it leaves the building via open doors. This approach can result in fuel savings of up to 75%, compared with conventional heating systems in a similar application.
Whilst heating a building during the winter is a necessity, cooling a building during the summer is just as important, especially to achieve comfortable working conditions, which will ultimately lead to more efficient performance from personnel. However, selecting a heating and cooling system, unlike a heatingonly system, is best suited to those applications that operate a ‘closed door’ policy otherwise all the energy will escape through those open doors.
However, there are solutions for achieving heating and cooling. Gas fired air heaters (such as those offered by Reznor) can provide combined heating and ventilation with the option of cooling. Units are available as either indoor or outdoor models with a wide range of heat outputs and cooling capacities. Air volumes are model-dependent but range from 0.47m3/s up to 3.88m3/s with external static pressures of up to 400pa available. When cooling is incorporated within the unit heaters an external condenser/ cooling unit is required.
Another method of achieving heating and cooling is the use of packaged rooftop units (which can also be used on the floor outside) that are fitted with heat pumps providing a range of cooling and heating outputs. Additional heat is available by selecting the optional gas fired heater section.
Curtain up
Packaged rooftop units were used at the Victoria Palace theatre in London, which recently updated its cooling and heating system.
Theatre owners, Delfont Mackintosh wanted to renovate the hvac systems to ensure a consistent and comfortable temperature throughout the building. The upper circle could be sweltering in 28oC while at the same time the audience in the stalls were cooling their heels in temperatures as low as 19oC. The client saw several technical design options and sketch-up models by the project team, which included Buro Happold and contractors Mechanical Services.
The project team provided the most appropriate HVAC heating solution which involved the installation of four Reznor packaged units, located on the roof of the theatre. The roof-top unit (RTU) is composed of airto- air heat pumps in packaged rooftop configurations with a DX coil and condensers to work as a heat pump to provide both heating and cooling modes, as well as optional preheat via electric or gas fired coils. A key benefit of the RTU system is that the units can be installed without the need for any structural alterations to the building.
The four RTU’s provide ventilation to the main auditorium, this air is either tempered or cooled dependent on the required demand. To maximise the efficiency of the system a Heat Pump configuration was selected to provide both heating and cooling. With indoor air quality being an ever-present driver in modern built environment design, the RTU satisfies occupancy ventilation requirements.
The system now provides a comfortable working environment to theatre staff and members of the audience adding to their overall experience. Installed in 2017, the system has really been put to the test through one of the UK’s coldest winters and hottest summers.
Danny Packham is European product manager – Warm Air and Radiant for Nortek Global HVAC UK
