The combination of the monumental building, the Rotonde, and the panoramic painting ‘Panorama Mesdag’ is one of the few remaining exhibitions of its kind. The organization of the museum aims to preserve the building and painting while also wanting to decrease the carbon footprint of the museum. The objective of this research is to design a sustainable climate solution using thermal buffering that creates an indoor climate that preserves the panoramic painting and reduces energy consumption of the minimally insulated building. The potential thermal buffering solutions were defined through literature research and the option of a PCM system secured to the interior façade was further elaborated on by estimating its effect on the indoor climate of the Rotonde through software simulations in DesignBuilder using EnergyPlus. The simulation results of multiple PCM types and thicknesses showed that the current indoor temperature of the Rotonde is too inconsistent during summer months for a PCM to reach the intended cooling effect. A simulation of a combination of improvements to the building envelope and the most effective PCM showed a cooling effect of two ° C on warm summer days and a decrease of 50% in heating demand during the winter. This research amplifies the importance of a well-insulated building envelope for a qualitative indoor climate and climate systems should be an additional step. The outcome of this research has the potential to be relevant for other monumental museums or other spaces that seek sustainable solutions to stabilize the indoor climate.

Despite being a critical aspect in improving the building stock’s environmental performance and achieving the global environmental goals, the retrofit of traditional historic buildings is hindered by a lack of comprehensive guidelines tailored to their complex building physics and heritage preservation requirements. The conventional retrofit approach – relying on the combined airtightness and insulation improvements – fail to address two decisive aspects of traditional historic buildings: First, the air leakage is a core contributor to their bioclimatic systems and building physics balance, making its sealing detrimental to their construction durability and their Indoor Environment Quality (IEQ). Second, their heritage protection requirements restrict the conventional retrofit interventions, and particularly hinder the implementation of the mechanical systems needed to mitigate their associated risks on the building and its occupants. Accordingly, there arose an interest in challenging the conventional depiction of the air leakage as an overhead to be eliminated, and in developing a retrofit approach that preserves breathable buildings’ inherent operations by exploiting their air leakage into achieving their optimal post-retrofit performance, accounting for both energy-efficiency and IEQ. A potential solution to the feasibility of such strategy considered a natural phenomenon characteristic of the diffuse leakage through breathable envelopes – the infiltration heat recovery (IHR) – that is conventionally neglected in building performance assessments. The intentional and efficient exploitation of this effect results in construction elements, referred to as Dynamic Insulations (DI), in which air leakage could act as a heat exchanger, diffuse ventilation source, airborne contaminant filter, and diffusion barrier. Although their original design and operations were not tailored to efficiently harvest the IHR effect, the existing breathable constructions reveal similarities with DI systems. This suggests the potential of retrofitting them to act as an efficient DI system, thus exploiting the air leakage into the building performance improvements. The present research aimed at identifying the envelope and ventilation retrofit variants that would optimize the IHR utilization through the construction, as to provide for performance improvements comparable to (or better than) the conventional approach while preserving the breathability of the construction and minimizing the heritage disruptions. The study proposes a comprehensive framework for the assessment of the building’s post-retrofit performance, in terms of its energy-efficiency and IEQ, and investigates the relevant retrofit variants to make performance-based decisions in the retrofit design for traditional breathable buildings. This performance was evaluated using a comprehensive building performance simulation (BPS) model. For a reliable representation of the complex building physics and air leakage dynamics of breathable constructions, the BPS integrates three sub-models: the building energy simulation (BES) model, the air leakage model, and the dynamic insulation (DI) model. Due to a lack of BES tools simulating dynamic construction properties, the well-established analytical Taylor model was adopted and adapted to the dynamic simulation tool. The analysis was implemented in EnergyPlus, for its integral Airflow Network (AFN) and advanced Energy Management System (EMS) capabilities. The model’s validation process revealed significant limitations and highlighted a need for BPS tools capable of more efficiently incorporating the dynamic behavior of building materials and their interaction with dynamic flows, particularly when seeking the tailored, efficient and non-intrusive retrofit of historic traditional buildings...

In this thesis the passive humidity control of indoor air is laid under review. This is primarily interesting for museum rooms, where strict requirements apply to the indoor air humidity. Passive humidity control is promising to contribute to stabilizing the relative humidity levels in a room. Besides, the use of passive humidity control can potentially reduce energy demand for (de)-humidification, and reduce HVAC dimensions as a consequence. This work has zoomed in on the (de)-humidification of air lead through a packed bed with silica gel beads. Silica gel is very promising to use as a buffer material for humidity control as a result of its high hygroscopic capacity, or slope of sorption isotherm. The work started with uptake rate measurements on different silica gel samples, referred to as Experiment 1. This has yielded adsorption and desorption isotherm between 20 and 80 %RH. The obtained isotherms provide insight in the sorption capacity of different samples, as well as the presence of sorption hysteresis. Samples with promising sorption and desorption behaviour were selected to include in an experiment with a packed bed. In this experiment, referred to as Experiment 2, silica gel was contained in a packed bed (column) and exposed to cyclic input: alternating high and low levels of relative humidity, using a step function. Both short (1h/1h) as well as long (8h/16h) cycles are executed in the experiment. In both types of experiments, significant dehumidification and humidification of air in the packed bed was measured. Next to experiments, a numerical model of the packed bed is developed. The results of this model are compared to experimental data from literature and to the experimental data obtained in Experiment 2. The model proves to be able to simulate the course of both temperature and humidity of outlet air exiting the packed bed in a reliable way. The main discrepancy between model and experimental results is found in the response time of the model: it reacts faster to changing inlet compared to measurements. Furthermore the model is sensitive to the inputted isotherm polynomial, RH(w). This polynomial describes the equilibrium of gaseous water in the air and adsorbed liquid water in the silica gel. This equilibrium applies at the interface of air and silica gel surface. Experiment 2 has shown silica gel is able to both adsorb and desorb water in the humidity range of 40 to 60 %RH. An important observation in the long runs of Experiment 2 is that more water is adsorbed than desorbed in the Ąrst cycles. Two issues can be mentioned to explain this: the samples can experience ŠprimaryŠ hysteresis: some water is permanently retained in silica gel during the Ąrst adsorption/desorption cycle. This is a plausible explanation for the difference in primary and secondary isotherms. The other potential explanation is sway-in behaviour: it takes some time before the effect of initial conditions is eliminated in a cyclic experiment. In this case, it is possible that some water is stored in the deeper layers of a silica bead. The moisture uptake and release by silica gel converges to an equal value. The performance in buffering moisture is expressed in the Moisture Buffering Value (MBV) in [g/m3/%RH]. This MBVτ accounts for the time period of the expected humidity fluctuations. The maximum, or theoretical, MBV∞ is derived from the equilibrium isotherm. For a given time period of the expected humidity fluctuations, the part of the hygroscopic capacity of silica gel that is effectively used is expressed as: ξeffective = (MBVτ / MBV∞) · ξtheoretical (1) The MBVτ is determind based on experimental results in this project. The numerical PGC model can serve as a tool to simulate MBV (and ξeffective) for different geometries of the silica gel container and different humidity input. Concluding, silica gel is well able to reduce Ćuctuations in relative humidity of indoor air. It is important that the silica gel is well reachable by indoor air. Uniform utilization of the silica gel will increase the effective part of the (theoretical) hygroscopic capacity, ξeffective in [kg/m3], of the silica gel. It is best to avoid long lengths of silica, since the effectiveness of ŠupperŠ silica gel is reduced. Relative humidity fluctuations can occur either due to changes in absolute humidity (hygric loads) or due to temperature Ćuctuations in a room. If relative humidity fluctuations are due to changes in absolute humidity, performance of the packed bed could be improved by cooling the silica during adsorption (dehumidification of air) and heating during desorption (humidification of air). Energy demand for temperature control of the silica gel should be limited, to not mitigate the profits in energy demand for passive humidity control.