A vast array of installations hidden in Paleis Het Loo

During the large-scale renewal and renovation of Paleis Het Loo, Heijmans took care of all the technical installations. Both in the buildings and on the grounds. A total of no less than 17 million euros worth of mechanical and electrical installations were fitted in, preserving the centuries-old grandeur of the palace. The contract marked the continuation of a longstanding collaboration, say project manager Frans van Kruijl and planner/project leader E Rudolf van de Kolk. In the past, Heijmans had also provided the E-technical maintenance of the museum for 13 years. This meant that the total installer was already very familiar with the value and functions of the various palace spaces, as well as the locations of the installation techniques. A godsend, because not everything was on drawings....

Among other things, Heijmans replaced the decentralized heating and cooling systems in the building sections with a central and modern installation. "Depending on the current outside temperatures, cold and heat demand, the most sustainable system was always used," said Van Kruijl. "Two 900 kW gas-fired boilers (total: 1.8 MW) were installed in the energy building, which can supply hot water up to 90°C. An important requirement, because the existing window convectors in the monumental palace section were retained. Thanks to the high supply temperature, the convectors can provide a comfortable indoor temperature even on the coldest days of the year. As soon as it can, however, more sustainable installations are used." On the site, Heijmans has realized a thermal storage system with a mono-source of about 800 kW, with a depth of 90 (hot source) and 155 meters (cold source). "A drycooler (785 kW) on the roof can be used for cooling and keeps the source installation in balance."

High climate class

Two 307 kW air-to-water heat pumps were also installed. As it gets colder, two indoor water-to-water heat pumps of 400 kW are additionally deployed to provide heat, says Van Kruijl. "As a delivery system in the new building sections, air heating in combination with underfloor heating and floor cooling, climate ceilings and a single radiator was largely chosen." The total air exchange is approximately 250,000 m3/h. "To make this possible, we installed 25 air handling units up to 40,975 m3/h. In addition, approximately 10,700 m2 of air ducts were installed." Thanks to the new installations, today's standards of sustainability, health and comfort are fully met. "Moreover, Paleis Het Loo now has rooms with a much higher climate class, for example with regard to temperature and humidity, which also allows it to borrow art."

Invisible elimination

To allow for greater fire compartmentation, the old palace section is fully equipped with a water mist system. "This system operates under high pressure, which means less water is needed to fight an unexpected fire," said Van Kruijl. "Thanks to a high cooling capacity, the escape time is also extended." To conceal the water mist system invisibly in the monumental palace spaces was quite a challenge. "The same goes for the incorporation of the E-installations," Van de Kolk explains. "Initially, we were going to keep most of the existing 230-Volt installation in the monumental palace section. With the large-scale asbestos remediation, however, installation parts were removed in many places. Understanding and reconnecting the remaining components was so complex that we decided, in consultation with Paleis Het Loo, to completely renew the installation. This was quite exciting. To determine the right places for the components and lead-throughs, we sometimes literally climbed the ladder together or crawled under the floors."

Substantial numbers

Heijmans moved the central power supply from the West Wing to the energy building. "Chosen was an indoor transformer with a capacity of 1,600 kVA from which one main distributor and about fifty sub-distributors are fed," Van de Kolk said. "In addition, an NSA and UPS are provided in the power building." All new lighting is done in LED. "A total of about 1,500 LED fixtures have been installed, as well as 6,500 meters of power supply and more than 1,000 data points for the benefit of the data installation." The museum lighting was replaced or refitted in-house by Paleis Het Loo.

During the renovation and remodeling, hefty numbers of installations were incorporated. "The techniques themselves were not challenging, that's our business," Van Kruijl emphasizes. "The invisible incorporation of them into the monumental spaces, however, was an entirely different story. The information was sometimes hard to find. We regularly scanned old drawings and took photographs, which were pasted on top of each other. On top of this, we also overlaid the old beam drawings, which were still drawn with a pen and ruler. That made this project very special, which also applies to a very last installation: the fountain installation in the courtyard, in which large numbers of pipes and pumps were installed to make an impressive water spectacle possible."