Energy-efficient and sustainable Tergooi hospital

Tergooi is developing a new hospital as part of the redevelopment of the Monnikenberg country estate to the east of Hilversum. The hospital is part of the supraregional health-care park that is being realised at Monnikenberg. The plan also involves new residences, landscaping and nature development, as well as opening up and increasing the accessibility to the estate. Tergooi has high sustainability ambitions when it comes to the development of the new hospital: the objective is to have it achieve an ‘excellent’ BREEAM® rating.


To achieve this, research was conducted into a number of innovative ideas which showed promise for application in the new hospital and would contribute to fulfilling the sustainability ambitions:

  • Introduction of the Pharmafilter®
  • Reestablishment of the energy balance by using the parking garage as a heat exchanger for sustainable cooling.
  • Introduction of a new concept for the production of hot tap water.

A quick-scan elaborated these options and evaluated their technical and economic feasibility. The economic feasibility was assessed by calculating the Total Cost of Ownership (TOC) of the options over a period of 40 years. To calculate the TCOs a substantial amount of data had to be collected or estimated as precisely as possible.


The quick-scan research showed that the realisation of all three systems was technically feasible. On the basis of the Total Costs of Ownership, the introduction of Pharmafilter® and the use of the parking garage for sustainable cooling were sufficiently promising to merit further elaboration. With regard to the third option, the context – the energy balance especially – was not yet sufficiently crystallised.

Based on the quick-scan results, the second stage of the research then focused on fleshing out the introduction of the Pharmafilter® concept and the re-establishment of the energy balance by using the parking garage as a heat exchanger.

The Pharmafilter® concept offers Tergooi clear sustainability benefits. One key element of the realisation concerns the choice of the location for the treatment. The availability of suitable locations needs to be quickly clarified. The reuse of the treated wastewater also offers interesting perspectives. Such reuse can however only occur under strict conditions. From a regulatory perspective, a dispensation would need to be given for the use of this water in the hospital. This would require specific technical measures to prevent the (re)used wastewater from posing any health risk. Further research would be called for to determine what conditions need to be met to enable water reuse for flushing toilets and Tonto® shredders.

Because new hospital in Hilversum will be very well insulated its energy balance will be determined primarily by processes that take place in the building itself. At the current stage it is still not possible to make a good estimate of the heat surplus or deficit. The current assessments point to an annual heat surplus of 7.7 TJ and the need for cooling of the same magnitude. Due to the uncertainties about the heat surplus, we also carried out calculations for a heat surpluses of 3.6 and 10.8 TJ. In most cases the use of dry coolers is more advantageous than the sustainable options, which involve capturing the winter cold. Installing systems in the ceilings of the parking garage, or incorporating heat exchangers in the façade cladding of the technical spaces using steel central heating pipes, are financially feasible under specific circumstances. With respect to the sustainable cooling, no recommendation can yet be made, except to say that the energy balance of the new hospital needs to be clarified as soon as possible to provide an accurate picture of the cooling capacity required. Based on this information, a choice can then be made among the options available for sustainable cooling or dry coolers.

The project gave Tergooi more detailed information on a number of possibilities for the implementation of sustainable energy- and water-technology solutions. The knowledge and insights acquired can also help other health-care institutions and building proprietors in designing energy-efficient buildings. By collaborating closely with companies, knowledge institutions and the end-user, in a short period of time a good underpinning was provided for this choice of building. Tergooi will use it in deciding how to organise energy and water management in the new Hilversum hospital.