A hypocaust hot air floor heating system in the Netherlands

In 2002 a PhD study was finished on heating monumental churches at the Eindhoven University of Technology. Most of the heating systems used in the Netherlands were examined. At a number of places, which were not investigated in the mentioned study, unique heating systems are applied. The Stevens church is heated by a hypocaust heating system: floor heating by hot air transported through a constructive duct system of bricks underneath the floor. The system is not energy efficient. The purpose of this research is to design a more energy efficient heating system. Important aspects to be considered are the preservation of present monumental objects, the building itself and thermal comfort of the church visitors. The paper presents: (1) Measurements of the current indoor climate; (2) Simulation of the current indoor climate; (3) Validation by comparing measurements and simulations; (4) Simulation and evaluation of the design options. It is concluded that, although a hypocaust heating system almost satisfies to preserve monumental objects and thermal comfort, the system is slow, difficult to control and it is not energy efficient. For a new heating system a hot air system would be adequate or a combination of under floor heating with hot water pipes as a base heating with additional hot air heating.