The renovation measures envisaged in the concept were completed by the end of 2012. Essentially the measures affect the generation of heating and cooling, distribution systems, the hot water supply, and IC technology. The primary energy for heat generation was converted to natural gas, and an 8.8 km long pipeline was laid specially for the clinic to connect to the natural gas grid. The old boilers were replaced with two combined heat and power units (CHP) and a new boiler unit. The CHPs cover the clinic’s base thermal load. Two power units supply 140 kW electrical and 207 kW thermal output each. Added to that are two low temperature boilers, each with 2 200 kW output and 200 kW waste-gas heat exchangers. When needed, the boilers can handle the entire heat load of the clinic, which means that a heating supply is fully guaranteed even if the CHPs are down. For safe operation the heat generators (boilers as well as CHPs) are hydraulically decoupled from one another. For this a Zortström distribution system is used, which decouples both generators as well as consumers. Layer separating plates allow optimal integration of the individual consumers, and a higher differential temperature between supply and return water pipes.
For the cooling supply the two existing systems, which had been separate until then, were joined together hydraulically, to be able to centrally supply all cold consumers in the existing buildings in future through the new cooling system in the surgery center. But because one of the two existing cooling generators didn’t offer enough operational reliability for the interim period, it was replaced as part of the renovation measures. Moreover, the existing water heaters with a total of 25 500 liters capacity were converted to flow generation systems, with heat exchangers. The heat is not retained any more through hot potable water storage, but hygienically safe through heating buffer storage, upstream from the plant equipment.
HIGH-EFFICIENCY PUMPS FROM GRUNDFOS
An important element of the energy renovations was a hydraulic balancing of the entire clinic complex, and the replacement of older circulating pumps. The entire heating system was recalculated, to ensure optimum design of the energy flows. To implement this, some 7 500 radiators were adjusted in the existing buildings with new pre-settings. With the optimization of heat distribution, it was possible to save around 5% of the heat energy.
The replacement of the circulating pumps resulted in considerable savings in electric power. Many of the existing pumps didn’t have any control systems and had power consumption ratings of up to 1 500 watt. In the course of the renovation work more than 40 existing pumps in the heat distribution system were replaced by electronically controlled high-efficiency pumps from Grundfos. In addition to two type TPE 100-70 electronically regulated inline pumps, particular use was also made of models of the Magna3 series. This versatile wet-runner series can satisfy an array of different needs. For the renovations in Vogtareuth a total of 47 Magna and Magna3 pumps were installed in the installation sizes of 25-60 to 65-120F. Most of them replaced inefficient pumps already in place, and in some cases (such as the supply lines of the new CHP units) they were new installations.
In addition to the heat generation and distribution systems, the analog IC technology was also replaced. The systems are now controlled and monitored digitally through a building services engineering system. A new fault monitoring system ensures that fault alarms go directly to the technician on duty and can be promptly rectified.