People who own old buildings often don't want to make any fundamental changes to the air conditioning or ventilation system because this would presumably entail far-reaching modifications to the building structure; not to mention the problems with a listed building. Opening up walls, laying pipes and much more – in most cases this is not necessary at all since existing systems can to a large extent be incorporated into the planning. Furthermore, anything else would not be justifiable from the viewpoint of the potential energy savings.
However, it is necessary to determine the actual fundamental requirements. Changes in the number of employees or a modified fleet of machines will directly affect the requirements. The same applies for example when considering additional solar energy system or heat pump installations.
The system must fundamentally be assessed and re-calculated as a whole. Thanks to today's far more precise methods for calculations and performing simulations, the building situation and the requirements for the air conditioning or ventilation system can be coordinated together very precisely. As a result of the improved technology of electric motors and fans, the amount of space required for these components can be significantly reduced.
Using the latest data, experts determine the ideal components: the latest generation of electric motors, control units and fans. In this context, there is no single, ideal combination. The owner of the building is provided with a comparative payback calculation; together with multiple versions of components that meet the requirements of his/her energy savings plan.
Majority of the existing plant remains unchanged
In most cases, a large part of the existing plant can be left unchanged. The focus of the attention is on electric motors, control units and fans which in any event will be replaced by more efficient, new devices. Since large fans are often awkward to install in existing buildings, the trend is towards units which are smaller but that work together in parallel. This also has the advantage of enabling individual components to be easily maintained or replaced whilst the system is running. Ziehl-Abegg has developed the modular fan system for this purpose, the ZAcube: multiple cube-shaped elements are installed on top of and next to each other, like a modular system; aerodynamically optimised fans and energy-saving EC motors are integrated into each cube.
Semiconductor manufacturer reduces energy consumption by 27 percent
A sample calculation from a case in practice: the air intake system (approx.155.000 m³/h) of a manufacturer in the semiconductor industry had become outdated. As part of a vigorous programme of retrofitting, three medium-pressure axial fans were replaced with a multiple-fan array. The result: energy consumption was reduced by 27 percent. As the 27 new individual fans distribute the air flow more evenly than the three old large fans, this has a positive effect on the lifetime of the filters.
Noise is unhealthy – and people are reacting with increasing sensitivity to unnecessary noise. That’s why noise emissions are also taken into consideration when carrying out retrofitting. For example, prior to the retrofitting, the air inlet system of the semiconductor manufacturer generated the same level of noise as a petrol-driven chain saw at a distance of one metre – after the retrofitting, this level now equates to that of a diesel engine at a distance of 10 metres.
Prior to the retrofitting
After the retrofitting
109 dB (A) at x m
88 dB(A) at x m
Nominal volume flow of 153.600 m³/h
Irrespective of the positive economic considerations, the retrofitting of ventilation or air conditioning systems must also be seen from the general environmental aspect. Energy is finite and in the interest of future generations should not be wasted.
Ziehl-Abegg (Kuenzelsau, Baden-Wurttemberg, Germany) is one of the leading global companies in the field of ventilation, control and drive technology. Back in the Fifties, Ziehl-Abegg established the basis for modern fan drives: external rotor motors which even today are still seen as state-of-the-art worldwide. Another area of business is electric motors which provide the power, for example, for elevators, medical applications (computer tomography equipment) or deep-sea underwater vehicles. The theme of electro-mobility for motor vehicles was established as part of the Ziehl-Abegg Automotive Team in 2012.
The high-tech company has an impressive innovative capability. Ziehl-Abegg employs 2,200 personnel in its production plants in Southern Germany. The company has a global workforce of 3,900 spread between 16 production plants, 28 companies and 108 sales locations. The products, approx. 30,000 in all, are sold in more than 100 countries. Turnover in 2017 totalled 540 million euros, with exports accounting for three quarters of the figure.
Emil Ziehl founded the company in Berlin in 1910 as a manufacturer of electric motors. After the Second World War the company’s headquarters were relocated to Southern Germany. Ziehl-Abegg SE is not a listed company but instead is family-owned.
For more information go to www.ziehl-abegg.com