VEMA: Twice as useful—when your cooling system also provides free heating
With comprehensive solutions from a single source—ranging from product development and toolmaking to highly specialized manufacturing processes—VEMA has established itself as an innovative plastics systems partner with a strong market position across various industrial sectors. Having enjoyed success in its core business for many years, the company has also set new standards in energy efficiency and environmental responsibility with its new facility.
Starting from very humble beginnings in 1982, VEMA GmbH in Krauchenwies-Göggingen, with its divisions in tool and mold making as well as technical plastic parts, is now one of the top choices for discerning customers. Its international customer base ranges from the automotive industry to sanitary, measurement, and medical technology. “With our expertise, reliability, and flexibility, we strengthen our customers’ innovative capabilities and thereby foster a trusting partnership—the foundation for the continuous expansion of our national and international business relationships,” explains Werner Veser, managing partner.
The company’s growth is reflected in its steadily increasing workforce and the new corporate headquarters built on a greenfield site in 2012. Spanning a total floor area of approximately 6,000 square meters, the facility houses the toolmaking shop—equipped with state-of-the-art machining equipment—the plastic injection molding shop with 30 high-performance injection molding machines, and the administrative offices. In terms of energy optimization, a holistic concept was implemented that serves as a model for energy-intensive businesses. “With the new building and the building services technology installed within it, we wanted to demonstrate that, as an energy-intensive business, there is much that can be done to sustainably reduce energy costs and environmental impact to a minimum,” says Christian Veser, describing the company management’s intention regarding the energy strategy of the new facility. “For this reason, we brought in the experts from ONI-Wärmetrafo GmbH to plan and implement the energy concept; they were able to convince us with reference projects and a coherent concept tailored to our specific situation.”
Against the backdrop of continuously rising energy costs, every plant operator today is interested in reducing their energy consumption as much as possible. The only question is: how, and at what cost? At first glance, the system design of the energy technology is somewhat easier when it comes to a new building. At VEMA, thanks to their own experience, they have headed in the right direction. The basic concept was designed so that cooling energy production is ideally adapted to the operating conditions and outdoor temperature, and the energy used is utilized multiple times.
All in a circle
The facility manufactures high-quality plastic products, such as design components, optical parts, and visible parts, using approximately 30 plastic processing machines with clamping forces ranging from 250 to 2,500 kilonewtons. A reliable year-round supply of cooling water at a stable temperature is essential for the production process, both for the machines’ drive units and for the complex mold systems, in order to ensure a mold surface temperature optimized for the process. Instead of the cooling tower systems previously used, which caused problems with cooling water quality and required complex chemical handling, VEMA now uses air-cooled free coolers for the cooling water supply to these areas. These recooling units impress with their optimal power adjustment to actual power requirements and consume extremely little electricity in the process. The units, equipped with a so-called adiabatic system, are capable of ensuring the cooling water supply in summer even at higher outdoor temperatures. A particular advantage of this open-loop cooling system used by ONI is that it is glycol-free. Glycol is classified as a water-polluting substance and, under the Water Resources Act, requires special safety measures, compliance with which often involves significant technical effort on the part of the plant operator. To avoid this problem from the outset and not place an unnecessary burden on the plant operator, these glycol-free systems were selected.
Security of supply guaranteed
Meeting delivery commitments is a key requirement that customers place on their suppliers. This requirement becomes particularly critical when parts must be delivered just-in-time or just-in-sequence. To be prepared for all eventualities, VEMA therefore planned a cistern cooling system in parallel with the recooling system featuring glycol-free free coolers. This not only creates performance redundancy but also provides a means of covering peak loads or cooling loads during periods of extreme outdoor temperatures.
In addition, the cistern cooling system offers a pleasant side effect. During periods of intense sunlight and high outdoor temperatures lasting several days, even the best thermal insulation is unable to keep the outside heat out of the building. In this case, the cistern cooling system is used to bring company areas to a temperature level at which concentrated work is possible.
Cooling saves on heating costs
Heating a facility with several thousand square meters of production, office, and warehouse space during the transitional and winter months—while also providing hot water for showers and sinks year-round—typically requires a significant amount of natural gas or heating oil. Consequently, heating energy consumption and the resulting operating costs are not insignificant. In addition, this heat generation system requires a boiler room equipped with a boiler, burner, and exhaust system. Thanks to the heating energy supply concept developed by ONI, energy used once at the Krauchenwies-Göggingen site is simply utilized a second time. This not only saves a great deal of energy but also eliminates the need for investments in a boiler room. “We have waste heat available from a wide variety of areas, but we haven’t utilized it in the past. With the new heating concept, we’ve turned the previous situation on its head, and the result is overwhelming even for us,” says Christian Veser, commenting on the savings potential achieved through waste heat utilization. The basis of the new heating energy concept for VEMA is the use of waste heat from the cooling of injection molding machines and tools at a temperature of 35 degrees Celsius, as well as from compressed air generation at approximately 70 degrees Celsius. Even today, this waste heat is simply released unused into the atmosphere via recooling systems at many industrial facilities, causing unnecessary environmental pollution.
Thanks to specialized industrial and office heaters, as well as an underfloor heating system from ONI, this temperature level is entirely sufficient to ensure adequate heating of all operational areas during the heating season, even when outdoor temperatures are extreme.
Low-temperature heating technology also has an additional positive effect that should not be underestimated. Office and hall heaters are capable of achieving ideal temperature distribution within the room. The relatively small temperature difference between the heating outlet and the room air temperature results in the best possible, homogeneous mixing within the room and a pleasant indoor climate compared to the high-temperature heating systems often used.
For a hygienically sound, centralized drinking water supply, storage or instantaneous systems are necessary, which are supplied with heating water flow temperatures of 70 degrees Celsius and higher. However, if peak consumption is expected during shift operations, so-called instantaneous systems are not suitable due to the high connected loads. In any case, however, such drinking water systems require heating suppliers that must operate in priority mode to deliver the required flow temperatures. Experience shows, however, that such heating suppliers operate with an extremely low efficiency rate over the course of the year, which in many cases falls below 50 percent.
Instead of a boiler or water heater, VEMA uses waste heat from compressed air generation to heat drinking water, because the cooling system for the air compressors provides cooling water at just over 70 degrees Celsius all year round!
During VEMA’s three-shift production operations, a total of more than 200 kilowatts of usable waste heat is continuously available for heating purposes from various areas. This waste heat utilization offers the operator a financially attractive dual benefit. Waste heat, which previously had to be recooled at great expense, is converted into free heating energy by ONI technology, massively reducing heating costs—which is particularly valuable in times of rising energy costs. Furthermore, the energy required to operate the recooling units is drastically reduced, at least during the heating season. Trust is good, verification is better. Most of us are surely familiar with this saying, as it simply reflects life experience that we may have encountered ourselves in one situation or another.
Plausible economic feasibility studies and exemplary reference projects can certainly be helpful in the decision-making process, but it is nice to be able to check the projected savings and the operational status of the system at a glance. In the case of VEMA, the company’s management wanted precisely this capability so they could evaluate their decision to install an energy-optimized system in hindsight.
A control system was therefore installed that consolidates and analyzes all relevant system data and visualizes operating conditions.
At the heart of the system is a PLC module equipped with energy-optimizing ONI system software developed by ONI, which acts as a dynamic management system to organize the energy supply at VEMA. This is where all information regarding the system status of the entire plant is collected and analyzed, and from here, the key system components receive all necessary commands. For example, the control system immediately detects when a peak load requires the activation of cistern cooling or in which area waste heat recovery is currently possible. This ensures that only the primary energy consumption that is absolutely necessary is used at any given hour. If heating is required in a specific area of the facility, the corresponding power is provided from the machine cooling circuit. The resulting reduction in recooling capacity, in turn, leads to a reduction in free cooling capacity, which saves additional electricity.
“With the ONI experts, we have brought the right partners on board to ensure an energy supply for our company that is optimal from an economic standpoint. We were surprised ourselves at how much energy consumption can be reduced with an optimized energy system. In our opinion, our holistically optimized energy concept has created the best possible starting point for continuing to operate a particularly economical and thus cost-saving energy generation system in the future. As a result, we expect continued business growth in the future and have therefore opted for a modular energy system. This system design allows us to make the necessary capacity adjustments at any time resulting from production expansion,” concluded Werner and Christian Veser regarding the implemented energy concept at VEMA.
