With increasing adoption of modular construction in the residential sector, its adoption in the Dutch healthcare sector is studied. Whilst the initial costs can be higher, this method of construction claims to have cost benefits over conventional construction. These are the benefits of construction speed and residual value at the end of lifespan amongst others. Modular buildings are also often advertised as sustainable, because the credentials gained from lean manufacturing coincide with a selection of sustainability objectives [1]. Healthcare projects have higher requirements and process hurdles, which make construction in healthcare much more complex than in the residential sector. However, in the UK, a study of offsite manufacture and modular volumetric construction methods concluded it to be the cost efficient solution necessary for the NHS, which led to 40 modular hospitals planned to be built until the year 2030 [2]. This means that the benefits and drawbacks of a modular approach must be weighed, and this is done in the Dutch context. A life cycle costing is proposed as the fitting tool of assessment.

Interviews were held with Dutch modular contractors to reveal the capabilities and specifics of building in a modular way and find proof for each cost factor. Experts in healthcare construction were interviewed to determine healthcare project priorities and find out whether these are catered for by modular construction. A live construction project of a hotfloor department was then studied. Several options competed in the tender project and were compared in the case study. By collecting the cost quotes and arguing for the monetary value of the identified cost factors, a life cycle cost calculation was done. Additionally, sustainability was considered by calculating the novel carbon tax. To expand the application of results to other projects, sensitivity studies were carried out for each life cycle cost parameter.

The study found that there is application for modular construction in healthcare in the Netherlands. Facilities, which do not host medical installations, do not differ to the construction used in residential modules. As for facilities such as the studied hotfloor department, larger modules and a lesser degree of finish offsite decreases the competitiveness of this construction approach. However, several evident cost factors were proposed to be considered within a life cycle costing. These were earlier income due to faster construction, a gain due to less interest and the residual value. It was found that these considerations allow for a 49,0% increase on the initial cost of a modular option in comparison to a conventional option. A hypothesis was further proposed, stating that the competitiveness of the modular option depends on three criteria. These include the initial modular option costs being up to 49,0% more expensive; the saving in construction time having a monetary value to the client; and life cycle costing results being used in total cost comparison.

EPA: Multi-Modelling for Complex Challenges With the acknowledgement of international grand challenges, the demand for better and ever more complex models is likely to increase a manifold. Where single models may no longer be able to grasp the complexities of a system, multi-modelling (Nikolic, Warnier, et al., 2019; Vangheluwe, 2000) enables the combination of the strengths of different models whilst enabling the development of multi-perspective insights. In this research, I developed a multi-model to provide policymakers in The Netherlands with insights on how to steer the Urban Energy Transition at both national and municipal level. This is done by combining a System Dynamics (Forrester, 1961) model for evaluating market behaviour at the national scale, and an Agent-Based Model (Epstein & Axtell, 1996) for investigating investment behaviour at the neighbourhood level. The results from experiments with this model show that multi-perspective insights can be very helpful in designing policies and strategies for dealing with Sustainable Urban Development. It is found that challenges concerning the conceptualisation phase of the Model Development Cycle, could turn out to be opportunities for model development. As formalism selection and possible overlapping scales between models requires extra effort and attention, this attention results in model concepts that will be better evaluated, resulting in better concepts to be developed altogether. The main challenge that is currently unresolved, is that of the computational performance of multi-models. Although worsened by the choice for Agent-Based Modelling as one of the formalisms used in the multi-model, the computational requirements for the simulation seriously hamper the opportunities for experimentation and analysis. Although solutions can be found to minimise the computational demand or the effects of it, improvements are required in either computational demand or processing supply, for multi-models to become a suitable method for common modelling and simulation practice. CME: Energy Transition in the Built Environment With the EU goals (European Commission, 2018b) to reduce CO2 emissions to zero tons in 2050, The Netherlands has set up a climate agreement (Klimaatakkoord, 2019) in which municipalities get a leading role in reducing the carbon footprint of the Built Environment. To realise these goals, an energy transition is inevitable and strategies need to be developed for remodelling neighbourhoods into sustainable living environments. Before the end of 2021, municipalities have to come up with a plan in which they decide what neighbourhoods will be transformed and when. A problem in this is that currently, municipalities do not have the resources and tools to do so (RTL, 2019; Schuttenhelm, 2020; Straver, 2019). Currently, existing models, such as the Vesta MAIS model (Planbureau voor de Leefomgeving, 2019c) offered by the national government, are missing two crucial aspects which should help municipalities to set up their strategies: time dynamics and population dynamics. The techno-economic approach does present the ’best’ solution but is missing how to get there. Next to this, uncertainty around national policies makes that it is very difficult to decide on a robust policy. To deal with the aforementioned challenges, I use a multi-modelling approach (Nikolic, Warnier, et al., 2019; Vangheluwe, 2000), using System Dynamics (Forrester, 1961) and Agent-Based modelling (Epstein & Axtell, 1996) in which on the one hand, the time dynamics and population dynamics aspects are incorporated, and on the other hand multi-perspective insights on effects of national policies on national goals as well as insights on the heterogeneous effects at the municipal level are provided. An important finding is the crucial role of a CO2 tax on the realisation of national goals. Without this tax, homeowners and housing corporations will not be motivated sufficiently to significantly invest in insulation measures, making that fewer alternative heating systems will be implemented. Next to this, it is found that major differences can be distinguished between rural and urban areas. Heating grids will be a viable starting point for urban municipalities to start their transition due to the availability of residual heat. For rural municipalities, this will be more difficult due to a dependency on low-temperature systems. There, starting with the neighbourhoods that have the most potential to insulate is advised.

Residential space heating demand in the Netherlands is met by natural gas boilers in 93% of Dutch households. In order to combat global climate change and limit the increase in global average temperatures to below 1.5°C by the year 2050, the Netherlands will have to cut down its emissions across all sectors of human activity to nearly zero. The residential space heating sector accounts for majority of the emissions of the built environment, decarbonising this sector is key to eliminating greenhouse gas emissions and combating global climate change. Decarbonisation of the residential heating sector can be achieved through multiple pathways. The aim of this thesis is to investigate which pathway would have the least cost to the end user in the year 2050. Three pathways have been selected, the all-electric pathway based on using heat pumps to meet space heating demand, the core hydrogen pathway based on meeting heating demand with end-use hydrogen boilers, and the hybrid pathway based on meeting heat demand with hybrid heat pumps. Electricity supply in all three pathways will come mainly from solar photovoltaic energy and wind turbines and hydrogen will be produced by electrolysis of water, from renewable electricity. Hydrogen is assumed to be transported directly to end-user households using the existing natural gas transport infrastructure of the Netherlands, with adequate safety modifications, after being produced by dedicated offshore wind turbine capacity. Hydrogen is not produced at all in the electric pathway. First, the heat demand per household (space heat + domestic hot water) is determined for each of the five types of dwellings in the Netherlands. Annual energy cost per household is then determined from projected future electricity and hydrogen retail prices. The installation of heat pumps will also involve renovations to the home to improve insulation levels in order to maximise the coefficient of performance, at additional cost to the end-user. The total annual cost per household of each pathway is then determined as the sum of the annual energy cost per household, the investment and installation cost of each device per household, and the annual maintenance cost. Total annual cost per decarbonisation pathway is the sum of the total annual cost per household for all houses in the Netherlands in 2050. The annual cost per household varies widely depending on the values of electricity and hydrogen tariffs in 2050, the capital investment cost of each device, the level of household renovations required to improve household insulation levels, and the cost of investment in devices such as low temperature radiators. Annual costs vary among different types of dwellings, the smaller the dwelling, the smaller the required area to be heated. The annual cost per pathway was found to mainly have uncertainties regarding the device capital investment cost and electricity and hydrogen tariffs in 2050. To reduce uncertainties in results, a scenario study was performed. The scenarios were constructed to account for the variations in device capital investment cost found in literature for electric and hybrid heat pumps, and the variations in energy tariff (electricity and hydrogen tariff) estimates for 2050. In five out of six analysed scenarios, the hydrogen boiler pathway was found to have the least annual costs in 2050, with electric heat pumps being the most expensive pathway in these scenarios.

The residential and service sectors are responsible for the 39% of the total energy consumption. 80% of this energy is used for heating purposes. Achieving nearly zero energy buildings is a major goal for the near future. The design of an integrated electrical and thermal system can substantially help to reach such objective. The façade is the biggest area of a building and could be utilised to convert incident solar energy to electrical and thermal energy. In previous work (2019), the combination of building integrated PV modules with solar chimney on a façade was investigated to study its energetic performance. One of the main findings was that using the thermal energy from the photovoltaic modules on the air inside the cavity of the chimney is not possible due to its low quality of heat. It was concluded that the utilization of heat could be better by using auxiliary systems, like photovoltaic thermal systems for water heating. The aim of this work is to create a computational model to calculate the thermal and electrical performance of PV thermal (PV/T) modules combined with a solar chimney. Two new designs for better heat utilization where considered and compared. The first design is for the PV modules to be installed at the front of the solar chimney with fins (Fins design) and the second design is to couple the PV modules installed on the wall inside the solar chimney with water pipe system (Water pipe design). These designs are also compared with the same configurations but without the thermal systems (No fins & No water pipes designs). In addition, two new strategies are introduced to improve the performance of the model. The first strategy is the optimization of the solar chimney openings with respect of time for the highest power generation. The second strategy is the variation of the water mass flow with respect to time for highest water-thermal energy and optimum cooling of the PV cells. The model was developed in MATLAB and it is based on 2D finite difference transient implicit method. To reduce the computational time, the density of the nodes varies in respect of temperature gradient. In addition, secondary models were created to increase the accuracy and sensibility of the model such as water tank and water pump models. The models were studied for a building in Delft, Netherlands, and the scale of the chosen system is 10m2. It is concluded that Water pipes design provides the overall best energetic performance mainly because of the high water-thermal energy with yearly energy efficiency of 64.3%. However, the best electrical performance is observed from the Fins design and the best air-thermal performance from the No water pipes design.

This project is based on two sustainable construction methods, namely up-cycling (reuse of materials) and vertical farming (green facades). These two concepts are combined to form a ‘Do It Yourself’ double skin façade, a double skin façade made with re-used sliding doors, which is aimed to be capable of developing ‘Edible Green’, which refers to the placement of edible vegetation in the façade of an office building. As two sustainable methods are combined into one project, the investigation of the performance of this ‘Do It Yourself’ double skin façade arose as an objective. Hence the aim of this research was to investigate the climatic performance of the façade for the growth of plants, as well as its influence in the indoor environment of the office. The façade was divided into 6 modules across two floors, capable of accommodating vegetation individually. These modules were assigned different design strategies based on ventilation, shading system, watering system and the placement of plants. Five different types of plants were placed on each module. Three types of ventilation strategies were adopted as parameters for the modules, namely minimally ventilated, naturally ventilated and mechanically ventilated. The configuration of plants were such that all modules had a total of 9 plants, with 7 short growing and 2 tall growing plants. The watering strategy was adopted in the form of drip irrigation system, where the modules in the top floor received constant rate of irrigation whereas the modules in the bottom floor received varied rate of irrigation. A measurement system was developed using a microcontroller, namely the Arduino UNO. The parameters were evaluated by the placement of measurement sensors in each of the modules. The measurement was done over a period of three weeks where the temperature, relative humidity, illuminance, CO2 and Total Volatile Organic Compounds (TVOC) were measured. The obtained values were studied and analysed based on the expected behaviour from the literature. The condition of the plants in the cavities were evaluated by determining the yield produced by each of the module, and also by a visual inspection of the plants. It was observed that the plants play an influential role in increasing the humidity in the cavity, especially in the cavities of the non-ventilated modules. This was evaluated by comparing the relative humidity and absolute humidity of all the modules. It was found that the humidity in the minimally ventilated modules was higher compared to the rest. Moreover, it was found that the shading in the façades highly influence the temperature in the cavity. The performed experiments suggested that the use of plants in the double skin façade, along with an external shading strategy can decrease the temperature in the cavity by up to 13°C and can increase the relative humidity of air in the cavity by 38%. Moreover, the experiments with respect to mechanically ventilated modules show that the cavity preheats the air by up to 6°C during night time and pre cools the air by up to 10°C during high outdoor temperatures (summer afternoons). Based on the theoretical and real time evaluation, it was concluded that the minimally ventilated modules perform relatively better with respect to the condition of the plants, whereas the mechanically ventilated modules perform better with respect to the indoor environment in the office. However, the influence of the double skin façade alone on the indoor environment of the office could not be determined, as there were external influences on the climatic conditions inside the office building. Based on the results, a design strategy was successfully formulated and the performance of each module was investigated. The research answered the question with respect to maintenance of the double skin façade for the growth and health of the vegetation. Moreover, the research helps to provide ideas on different design strategies that can be used, based on different sustainable design requirements.

Our excessive need for new building materials is causing our natural material stock to be depleted at an alarming rate. What happens if our most common building materials can no longer be acquired? This thesis shows the potential in reusing buildings and the components they comprise of by setting an example. An existing office building is transformed and expanded, where almost all building components the building currently is comprised of are reused, provided that they add to the building’s aesthetic, functional and environmental value. Additionally, surrounding buildings that are up for demolition serve as material resources from which additionally needed building components are harvested. The process of urban mining shall serve as a tool to make this possible.

Whilst research in solar cell materials lead to higher efficiencies every year, new difficulties arise with every breakthrough to get an even higher efficiency. Therefore, every component of a PV system should be examined, as well as how their behaviour under operation affects performance to improve the overall PV yield. In particular the temperature of a module can have a negative impact on the power output. The drop in power output is a consequence of a negative thermal coefficient that results in a decrease of open circuit voltage with increasing temperature. For silicon solar cells, efficiency drops of 0.4-0.65%/°C have been reported in literature. Moreover, daily repetition of temperature cycles can cause mechanical degradation, thereby decreasing the lifetime of PV modules. In this thesis, phase change materials (PCM) have been studied as a method to passively reduce the operating temperature of PV modules. This is based on the ability of materials to stay at a relatively stable temperature during a phase change. By placing a PCM at the back of a PV module, the temperature difference between the module and the melting PCM causes a thermal gradient, resulting in conduction of heat away from the
module. In order to find the optimal properties of a PCM, a thermal model was first developed in COMSOL Multiphysics and benchmarked with field measurements from literature. Simulations for Rotterdam, the Netherlands, revealed that an optimized PCM could increase the yearly electrical yield by 1.23% for a rack-mounted module, or 3.52% for a roof-mounted module. Furthermore, measurements were performed with commercially available PCMs under a Large Area Solar Simulator (LASS). These were able to reduce the average module temperature by 30-36°C, albeit under heavy infrared radiation coming from the simulator.