Large-scale CFD analysis requires extended time and computing resource, and in recent years reduced order modeling techniques are developed. Among many of these techniques, proper orthogonal decomposition (POD) stands out as a preferable method. POD allows the processing of large amounts of high-dimensional data with the aim of obtaining low-dimensional descriptions that capture much of the analyzed phenomena. Here, we discuss how POD is used to overcome the issues addressed from the traditional CFD method and show how POD can be used for data center analyses. Both CFD and POD methods are compared in terms of running time and accuracy.

It is challenging to properly control the ventilation in a complex built environment, such as a data center room and aircraft cabin. The ventilation effects depend on both an indoor airflow distribution and HVAC system. This presentation introduces a coupled simulation of three-dimensional indoor airflow and building HVAC system. The indoor airflow is simulated by a fast fluid dynamics program, while the HVAC and control system is modeled with a Modelica language. We will introduce the principle of the coupled simulation and demonstrate its usage for the ventilation control.

Traditional CFD methods have proven useful, though slow and complex, for data center applications.  Alternative, simpler technologies are becoming available which trade varying degrees of accuracy for speed and simplicity.  Potential flow modeling (PFM) offers nearly real-time steady-state modeling for practical applications and is best suited for estimates early in the data center design cycle.   The fast fluid dynamics (FFD) approach includes all of the physics of traditional CFD methods while being simpler to code and delivering an order of magnitude speed improvement for transient applications.   This presentation discusses PFM and FFD in the context of data center applications.

Major CFD computational penalty is caused by high requirement on spatial mesh resolution and this presentation shows the theory and practical feasibility of using coarse-grid CFD. It utilizes numerical viscosity induced by coarse CFD grid, coupled with simplest turbulence model. Case studies show that a uniform coarse grid can be applied, along with a constant turbulence viscosity model, to reasonably predict general airflow patterns. Such predictions is not as precise as fine-grid CFDs, but the accuracy is acceptable for indoor environment study at an early stage of a project. The computing speed is about 100 times faster than  fine-grid CFD.

High-efficiency equipment does not automatically mean high performance.  A brand-new multifamily building in New York City had all the bells and whistles: condensing boilers, multi-sensor BMS, and photovoltaics, among others.  Unfortunately, the building was not able to reap any of the benefits. This presentation will answer the following questions: 1. Why is advanced technology alone insufficient to deliver energy? 2. Is it possible to obtain acceptable energy savings with less-advanced technology? 3. When does it make the most sense to use advanced technology? 4. How can I increase the probability of obtaining promised performance out of advanced technology?

A mixed-use NYC high-rise was built in 2000 with advanced technology. An energy audit revealed that the BMS had unsupported controllers, an inadequate graphics card, sensors out of calibration and settings errors.  Benchmarking confirmed that O&M was inadequate and equipment was not operating as designed.  Additionally, staff were not adequately trained in the use of the equipment or the BMS.  As a result, the building's energy performance was worse than that of many 100-year-old steam-heated buildings. This presentation will cover the lessons learned from this case study.  Moving forward, what options are the most cost-effective way to achieve the intended performance of this building?

Over the last twenty years, variable frequency drives have become a widely accepted technology, consistently installed in new projects and retrofitted into many old buildings.  However, the energy savings potential of this technology is greatly limited by lack of training on their capabilities at the building level.  Especially where VFDs have been retrofitted onto old buildings, we often find them being used only for softstart or not at all. This presentation provides examples of a number of cases in which the potential of VFDs has not been maximized, and recommends adjustments to installation, training and operational practices that could address these issues.

Renewables integration into the electric grid was relatively inconsequential when the percentage was small.  With the penetration of solar PV and wind growing, the impacts of unpredictable availability are starting to show and the need for storage on both sides of the electric meter is becoming very apparent. A situational overview and a few case studies will be shared.

This presentation provides an overview of the impact of intermittent renewable energy technologies (notably solar and, especially, wind power) on the electric power grid.  Multi-hour energy storage (ES) technology options are described; and their technical and economical characteristics are compared.  The use of cool thermal energy storage (TES), in both demand-side (electricity user) and supply-side (electric utility generator) applications, is examined, with performance and economic results highlighted.  Examples illustrate the varied means by which TES can expand the use of renewable energy resources.

The demand for electricity in many locations is strongly driven by building air conditioning systems, which experience their peak in the afternoon period during hot humid days.  It seems reasonable to assume that utilities would benefit from increased renewable energy deployment to meet electric loads from air conditioning because solar energy output is high when air conditioning demands are high.  This presentation explores this thesis in more depth and describes why renewable energy technologies alone cannot cost-effectively meet utility loads.  Thermal energy storage is shelf-ready technology that will be instrumental in shifting electric loads from air conditioning to periods of time when renewable energy is available.

Grid-interactive electric thermal storage (GETS) space and water heaters have an innovative communication and control system, when aggregated; provide ISO’s, utilities and aggregators the ability to precisely vary consumer energy usage to the real-time needs of the electric grid.  With rapidly growing amounts of renewable energy, aggregated GETS systems with real time control are a low cost energy storage solution that provide precise visibility, measurement and controllability for these aggregated energy storage assets. This system of grid-edge storage provides electric grid managers the ability to integrate, manage and fully utilize renewable energy generation.

The IIR Congress is organized every four years and gathers refrigeration researchers from all over the world. The 24^th Congress program included over 700 talks in 122 technical sessions and 14 workshops covering technologies from low-temperature liquefaction to refrigerated storage to heat pumping and energy recovery. Refrigeration, air conditioning, and heat pumping topics dominated. The presentation highlights the latest research and engineering results, and coinciding and diverging technical opinions.  The audience will learn about the state of the art of these technologies and promising technical solutions for ‘improving the quality of life while preserving the earth.'

We explore possible low-GWP refrigerants by defining optimal thermodynamic properties and comparing those to properties estimated for a database of millions of compounds. We find that the optimal characteristics are quite rare; additional fluids are eliminated because they are unstable or toxic. We then estimate the cycle performance of the remaining candidates and apply efficiency as an additional screening criterion. The result is a handful of low-GWP candidates, and even these present tradeoffs. We argue that these represent all the viable candidates for single-component, medium- and high-pressure refrigerants—in other words, we have hit the limits of what chemistry allows.

Over last twenty years microchannel heat exchangers (MHX) have dramatically increased their presence in energy conversion systems: from aircraft and automotive applications and expanding to residential and industrial refrigeration and air-conditioning. This presentation presents major issues impacting application of MHX as evaporators: 1) condensate retention/removal, 2) frosting/defrosting and 3) refrigerant distribution.  The physics of the issues are discussed along with directions for mitigating them. Particular attention is given to refrigerant distribution and potential of Flash Gas Bypass to improve it.  In addition, quantification of vapor flow reversal in MHX tubes is presented along with system improvements obtained by its removal.

It seems to be clear that heat pumps have a unique role in the energy system of the future. Barely any other energy technology can provide net primary energy savings, economic benefits to the users and reduced climate impact at the same time. The benefit of heat pumps are achieved in several ways; by system integration capabilities tying together different parts of an energy system for enhanced overall energy efficiency, by storage of heat to offset peaks and, if efficient enough, providing the most efficient way to heat buildings from a net primary energy perspective.

This seminar presents numerical investigation of air-side heat transfer and pressure drop characteristics for several different fin-tube type heat exchangers. Three different types of tube geometry and four different fins are considered. The CFD analysis is conducted by using commercially available software (ANSYS Fluent 6.3) for Reynolds number range of 35 -200, with the corresponding face velocity range of 0.3-2.0 m/s.  After verifications of CFD results using available experimental data, a series of parametric study for design parameters of fin geometry has been conducted. The CFD results are reported in terms of Colburn j- and Fanning friction f-factors.

It is well known that in heat exchangers for HVAC&R applications, the air-side is the dominant resistance. Significant effort has been devoted to improving the heat transfer performance of air-side surfaces. Conventional heat exchangers use round tubes or flat tubes but other shapes are seldom explored. In this seminar, an approach for shape optimization is presented that allows for full topology optimization of the heat exchanger tube for a given application. A prototype is fabricated using 3D Metal Printing technique and its performance is measured in the laboratory. The comparison of predicted vs. measured performance is presented and conclusions drawn.

Increased pumping power penalty and manufacturing costs are among the major limiting factors for further enhancement of heat transfer coefficients for single phase and phase change processes.  To develop next generation heat/mass exchangers that have better overall performance and can meet size, weight, and pumping power constraints while being cost affordable, one needs to utilize innovative designs, materials and manufacturing techniques. In this presentation we will review progress achieved in Phase I of a government-sponsored project in which a team of collaborators from academia, industry and sponsoring government agency achieved new levels of heat transfer performance on the air side.

The majority of metal 3D printing machines use low thermal conductivity raw materials such as titanium alloys, cobalt chrome alloys and steel alloys. Thus any parts built will have limited heat transfer capabilities unless action is taken to deliberately enhance this characteristic. One such action is to embed heat pipes into the part as it is being built. This talk introduces a number of additively manufactured heat pipes designs and compares their performance to off-the-shelf units.

This seminar discusses the use of dry and liquid desiccant technologies and how to apply them creatively for the treatment of outside air.  This includes a design that utilizes a combination of cooling tower water, chilled water and hot water that modulates with the outside air loads to either cool or heat the liquid desiccant to provide dehumidification or humidification of the outside air. Then, waste heat or onsite power generation to regenerate the liquid desiccant solution. A comparison of the technologies will be presented and the opportunities for both to provide comfort and energy savings to meet ventilation codes.

Liquid desiccant heat exchangers (LDHX) can improve the performance of many HVAC systems by replacing traditional finned-tube coils. Adding LDHX technology to a vapor compression system effectively raises the evaporator temperature, while still delivering dry air. It also enables separate control of sensible and latent cooling, ensuring occupant comfort in humid climates. This presentation will discuss (1) background on an innovative LDHX design, including a comparison to other liquid desiccant options, (2) modeling and laboratory testing of the LDHX modules, and (3) modeling of a 20-ton dedicated-outdoor air system using these LDHXs.

Air conditioners are made more energy efficient and can provide better humidity control by integrating liquid desiccant heat exchangers. This is the second demonstration of this particular liquid desiccant technology, with lessons learned from the first demonstration being applied to the second demonstration. The new system was completely re-designed from the ground up and has been reduced in size by over 50%. Furthermore, the new design reduces energy use by more than 33%, making the cooling cycle one of the most efficient options available today. This presentation will discuss the system’s new design, cycle improvements, and field test results.

Generation of electricity and air conditioning, one as a byproduct of the other, has the potential to enhance energy efficiency in buildings. In this seminar the potential for integrating fuel cell power systems with liquid desiccant air-conditioning systems is presented. This seminar will point out mutually enhancing features of liquid desiccant and fuel cell systems; provide a state of technology review; and provide details on integrated system performance in various climate and integration conditions.

This case study evaluates how the operable windows improve energy efficiency and indoor air quality for a state government office building. The IUB-OCA building is certified as Energy Star 100 and LEED Platinum. The measured energy use intensity is 21.5 kBtu/ft²-yr. One of low-energy sustainable design features is the operable window. The building automation system identifies favorable outside conditions and notifies occupants to open or close windows. The associated zone’s heat pumps are automatically shut down when windows are opened. The study analyses the impact of the operable windows on heat pump energy savings and occupant satisfaction through natural ventilation.

This study focuses on the investigation of the impacts of window operation on building performance for different types of ventilation systems including natural ventilation, mixed-mode ventilation, and conventional VAV systems in a medium-size office building. A building performance simulation tool—EnergyPlus—is used to simulate window operation for each system type. The investigation included the interaction between conventional VAV systems and window operation as well as control strategies for natural ventilation and mixed-mode ventilation. The results highlighted the impacts of window operation on energy use and comfort and identified substantial energy savings with mixed-mode ventilation during summer for various climates.

Light-weight, Internet-connected sensors are able to better monitor HVAC equipment, including economizers. Why maintaining economizers are the low-hanging fruit for improving rooftop unit energy efficiency and why over 50% of economizers are not functioning properly. How Internet-connected HVAC sensors with fault-detection and other diagnostic capabilities are able to better monitor economizer usage and aid in both installation and maintenance. What is being done with all of the data provided that is being transmitted to the "cloud" by these Internet-connected sensors?

Mobile software applications can work with Internet-enabled HVAC sensors to help HVAC technicians better install and maintain them. This paper shows how mobile apps can help technicians install Internet-enabled airflow, temperature, pressure, and other types of sensors. A step-by-step installation process shows how mobile apps can aid in fault detection and diagnose issues with HVAC equipment based upon data received from the sensors and mobile apps can better aid technicians in addressing these issues by displaying a decision-tree user interface.

ECM motor technologies have been used in wet running heating circulator pumps for years with substantial energy savings. These technologies are now being used on pumps for general HVAC applications. These new pumps with ECM motor technologies also include many new control options which reduce the energy usage of the pump and can contribute to the energy optimization of the overall HVAC system. This presentation gives an overview of these new technologies and the energy saving potentials.

Hydronic single-pipe heating systems have been used for decades and are renowned for their economic design and simple installation.  However, when a high delta T or a particularly low return water temperature is required, single pipe systems often fall short of achieving a high system efficiency. The use of traditional differential pressure controlled pumps is ineffective, as the single pipe systems are designed for constant flow. Therefore, a new approach is needed. This presentation provides a case study from an installation in Denmark where a temperature controlled pump has been used as the tool for obtaining higher system efficiency.

Advances in integrated variable speed drives and controls in ECM driven large wet rotor circulators make them an ideal fit for large residential and small commercial two pipe cooling applications.  This presentation will look at various ways to employ these pumps in primary-secondary and primary-secondary-tertiary pumping systems utilizing combinations of the T, DT, and DP functions of the circulator to effectively and efficiently cool and dehumidify the building.

The use of solar photovoltaics (PV) to provide comfort cooling will be presented.  The cost of solar PV installations has fallen, making the solar electricity competitive.  This discussion will cover techniques to best apply solar PV energy to cooling loads.  The "total solar cooling efficiency" of different methods will be compared for both solar PV and solar thermal.  Specific applications, i.e., PV driven air conditioning and heat pumps, energy storage, load mismatch, and PV with energy efficiency, will be discussed.  The shading effect of roof mounted PV arrays on HVAC systems and building loads will also be discussed.

While photovoltaic (PV) electric generation can be used for any type of load, peak generation often coincides with building cooling needs.  This presentation demonstrates how buildings with different types of mechanical systems match the PV output on an hourly daily, monthly and yearly basis.  Based on this data, a discussion on what it would take to get these buildings to net zero energy and  to the considerably more challenging goal of creating a micro-grid by adding an energy storage device and disconnecting from the utility.  The economics of PV cooling will be compared to the thermal cooling technologies.

Unitary rooftop equipment is commonly used for cooling in low-rise commercial buildings.  As PV module prices have dropped, feasibility of using solar for reducing purchased electricity has improved.   The simplest systems are utility-interactive.   There is a good coincidence between solar power availability and air conditioning power requirements since solar gain and outdoor temperature are inputs to building load.   Many low-rise commercial building have significant available roof area for solar PV arrays.  These relationships support the idea of using solar PV to  drive rooftop air conditioning equipment ito reduce purchased energy and the electrical demand on the utility grid.

Double-skin’s solar PV integration has been illuminated as a cost-effective HVAC refurbishment for worldwide implementation. The second facade as a glass skin is well suited for implementing PV elements. The presentation review: mathematical modelling of PV integrated double skin’s facade’s buildings physics (including construction structures relevant heat and mass transfer phenomena, energy conversion processes and balances); related HVAC’s cooling and heating dynamics and loads calculation method development; as well as prediction of PV electricity production and HVAC (including cooling) energy demand satisfaction via building’s performance co-simulation (coupling the CFD simulated air-flow within the double skin’s facade and facade/building energy simulation).

The new St. Vincent’s Medical Center Clay County was a collaborative effort between the design team, the commissioning team and the owner, Ascension Health.  From the beginning of the project, Ascension Health was an advocate of achieving optimal energy efficiency at the facility. TLC provided mechanical engineering services and designed high-performance energy-efficient systems. The St. Vincent’s Medical Center Clay County earned the Energy Star® rating of 97, which means the facility is performing in the top 3 percent of its peer facilities in the country for energy efficiency.

Many facilities require chilled water year round to serve fan coils or process loads.  This typically requires running a chiller year round or purchasing additional equipment to produce chilled water through free cooling cycles.  We will explore other opportunities for producing chilled water with and without implementation of cooling towers, heat exchangers and heat recovery chillers.

Many existing facilities, such as hospitals, operate inefficiently due to sequence and operational overrides that try to fix an issue at one point in time. As time goes on, many of these temporary “fixes” end up being permanent, building operation keeps deviating away from the original design intent, and typically ends up using a lot more energy. Through retro-commissioning and controls tune-ups, these facilities can identify issues and provide a permanent solution.

Radiant cooling and heating systems can potentially provide significant energy savings, possible peak load reduction, and better thermal comfort for the occupants. Such systems primarily depend on the radiant mode, instead of convective mode, for the transfer of heat within a space. These systems are often required to supply ventilation air to maintain certain indoor air quality and humidity in the space. The air flow patterns of the supply air and resulting buoyant airflows in the space can affect the performance of radiant systems. The flow rate and temperature of the supply air; location and type of supply air diffusers; and strength and location of interior sensible heat loads can affect the relative share of radiative and convective heat transfer in the space. This paper with the help of Computational Fluid Dynamics (CFD) analysis will evaluate the impact of various parameters of the supply air including the supply airflow rate, supply air temperature, and location and type of diffusers on the operation of radiant systems.

Between 1990 - 2006 the energy use of the ventilation systems in Swedish schools has doubled. This is mainly due to an increase of cooling demand which results in higher air-flow rates. In recent years many schools changed from displacement ventilation (DV) to mixing ventilation (MV), because MV causes fewer problems with thermal discomfort, although DV has higher ventilation efficiency. Studies show that 87% of Swedish schools use constant air volume (CAV) and it’s estimated that a change to variable air volume (VAV) could save 0.12-0.33 TWh per year. Therefore the aim of this study is to investigate whether it’s possible to replace DV with MV to create a comfortable indoor climate in a typical classroom and at the same time decrease the energy use by using VAV and Low Pressure Drop Ceiling Supply Device (LPDCSD).

This paper introduces a new model to simulate the energy performance of VRF systems in heat pump operation mode (either cooling or heating is provided but not simultaneously). The main features of the new model are the introduction of separate curves for capacities and power inputs of indoor and outdoor units instead of overall curves for the entire system, the allowing of variable evaporating and condensing temperatures in the indoor and outdoor units, and variable fan speed based on the temperature and zone load in the indoor unit. These features enhance the accuracy of the estimation of VRF system performance in both heating and cooling modes, especially during low part load operations.

The variable refrigerant flow (VRF) technology provides multi-split ductless configurations that typically use one outdoor unit (ODU) and multiple indoor units (IDU). VRF systems offer many advantages, such as elimination of duct loss of air distribution, design and installation flexibility, compactness, integrated controls, quiet operation and reduced maintenance cost. Also, multi-functional VRF (MFVRF) systems have achieved remarkable development, offering flexible operation of individualized zoning control, i.e. making possible simultaneous heating and cooling in addition to cooling or heating only modes. Meanwhile, such flexibility further complicates the operation and control due to diversified system configurations and highly variable operational loads. This paper proposes extremum seeking control (ESC) schemes for MFVRF system under different operational modes, in order to maximize the efficiency provided the satisfaction of thermal comfort.

Building energy systems often consume in excess of 20% more electrical energy than was the design intent largely because of equipment performance degradation (e.g. filter or heat exchanger fouling), equipment failures, or detrimental interactions among subsystems such as cooling and then reheating of conditioned air. Identifying the root causes of efficiency losses is challenging because a gradual erosion of performance can be difficult to detect.  This paper is focusing on the faults that are implemented using OpenStudio measures. These measures are created in OpenStudio Application or the Parametric Analysis Tool, which are written in Ruby scripts. These faults related measures act like add-on marco to make changes to the energy model to reflect faults.

Solar thermal cooling technology has incredible potential because the demand for cooling and supply of energy (sun energy) coincide. Solar radiation is at its peak, especially during the summer time where the need for air-conditioning is the highest. A well designed and installed solar thermal system can provide heating, cooling and domestic hot water. Thermally driven cooling technologies use harmless cooling fluids (usually water) compare to conventional cooling systems. This presentation will discuss the different components of a solar thermal cooling system, and will introduce the different types of technologies for thermally driven chillers as well as solar thermal collectors.

Peak cooling demand in summer is associated with high solar radiation availability. This offers an excellent opportunity to exploit solar energy with heat-driven cooling technologies, i.e. closed cycle systems (absorption and adsorption) and open cycles (e.g. desiccant systems). Practical insight as benchmarks from actual solar thermal assisted air-conditioning installations will be provided. Overview will include information on common systems, types of collectors, area/kWc, initial cost, design and actual thermal COP, auxiliary energy and water consumption. Monitoring data and experience from actual installations could provide some practical benchmarks to facilitate concept design and first cost estimates and further support standardized configurations and solutions for strengthening market development.

Gas fuelled tri-generation system is optimized by implementing solar assisted absorption cooling, heat recovery, thermal energy storage using ice; building's - thermal mass control via PCM, energy efficient lighting and daylighting control. Several packages of energy efficiency improvement measures are analysed, with the reference to the total installed power, cooling and heating energy demand, annual electricity and total energy demand, different control algorithms, as well as related investment and operational costs. It has been shown that, even for low gas prices and modest increase of electricity prices in the region, the optimal tri-generation system encompasses the solar assisted absorption cooling.

One of the four 10 kW systems on the South Hall of Orange County Convention Center in Orlando is a combined PV/thermal (PV/T) system where ambient air is drawn under the PV modules – improving their efficiency – and then ducted into a South Hall mechanical penthouse to regenerate a desiccant for dehumidification of a separate outside air supply to the building. The combined system was modeled by a graduate student for various absorber, regenerator, desiccant tank, and PV/T sizes to determine appropriate component sizing to meet a given ventilation load in seven locations across the US.

This paper discusses how the use of advanced engineering tools in HVAC industry has increased as the cost of computational fluid dynamics (CFD) has become more affordable for engineering firms.  We employed CFD in a design-build project in which conventional engineering tools were not sufficient to address the design challenges of developing an efficient chilled water thermal storage system. The system utilized a series of vertical tanks to store chilled water to supplement chillers in the event of a power failure. Chilled water is routed from the storage tanks to critical equipment during chiller re-start, bridging the gap in time that the chillers are unable to provide set-point chilled water due to power failure and subsequent required time to re-start.

As air conditioning (AC) has evolved from luxury to almost necessity, the rapid uptake of residential AC systems is creating major problems for our electricity network infrastructure, particularly on peak summer days. By using automated demand response (DR) signals, energy service providers aim to constrain the electrical demand that these systems place on the network. One such DR signalling scheme is Australian Standard 4755.3.1 that defines how air conditioning appliances respond to a set of initiating signals for reducing energy consumption. This paper highlights potential benefits obtained when performing ‘pre-cooling’ control strategies in summer prior to a demand response event.

Cyber security means many things to many people. Banking, government, utilities all have their own standards and terminology. All have the same goal to prevent disruption of operations, loss of sensitive data, and protection of life and property. But many of these standards are IT centric and are difficult to apply to the building control environment. One standard designed explicitly for automation is IEC 62443: Industrial Network and System Security. This presentation discusses how this standard can be applied to the automation ion the built environment, and how it differs from other cyber security standards.

The currently developing concept of net zero energy building should be adaptive for different climate situations. Buildings in the severe cold area of China have higher energy consumption and release gas emission due to large heating energy demand in wintertime. It is challenging to design and operate a net zero energy building in severe cold climate. This paper will discuss the feasibility of a net zero energy office building design targeting for energy efficiency and environmental sustainability from the initial planning, final construction, until the operation. An on-campus office building is studied as an experimental objective in Shenyang, Liaoning Province in China.

The global demand for electrical energy is increasing as a result of population growth and a higher standard of living that is enjoyed by many people.  However, the availability of electricity is often limited by fuel supplies and/or infrastructure for generating and distributing power.  In addition, the looming threat of green house gas emissions and the collateral damage to the environment has encouraged efforts to diversify methods of electricity production.  These factors have led to the increased use of renewable energy, particularly solar and wind, to help meet the demand for energy. In particular, the shift towards solar energy has been accelerating due to the decreasing cost of materials and installation. Universities are one possible location where solar electricity makes good sense.

As zero net energy (ZNE) buildings and other low-energy buildings become increasingly common it is important to consider how different ZNE strategies can interact with their local electricity grids. Demand response technologies and grid-sensitive design features in ZNE buildings will be critical to enabling the integration of these facilities into the grid at a large scale. The paper describes three tiers of DR and renewable energy technology integration in commercial buildings: Conventional buildings with one-way energy flows or conventional net metering. Moderately responsive buildings with interactive demand response capacity. Fully grid-integrated buildings with active and passive efficiency and demand response features, often with on-site renewable energy. This paper presents a framework for employing design strategies and measures that ensure buildings of the future can benefit from, and support, the grid modernization efforts that will occur throughout the life of the buildings.

The path towards zero energy buildings is fraught with many challenges, the onsite renewable energy production to drive consumer appliances that are not low or zero energy is an important challenge. Therefore, developing the energy production such that the production mode is matched to the usage is the simplest manner to improve efficiency.  As such, energy consumption for lighting could be significantly reduced by optimizing the building`s design to maximize direct daylight usage, similarly cooking using solar stoves, or water heating using solar geysers, reduce the need for PV cells electricity. The most important energy consumption in most buildings is HVAC (which accounts for approximately 40% of a building`s energy consumption) which can be addressed with the use of a solar power absorption chiller. This article introduces a design of a novel solar concentrated photovoltaic thermal (CPVT) system that produces electricity and thermal energy simultaneously from the same surface area.

Energy performance of buildings has an impact on the quality of the indoor environment. Nevertheless, the technical building systems can ensure the desired state of the internal environment, occurs in many low-energy buildings the deterioration of subjective perception and dissatisfaction of users. The paper focuses on issues related to the design of concept and controll of heating and ventilation systems in low energy residential and school buildings, and its impact on the quality of the indoor environment.

It is presented a case study of a building where an IEQ monitoring system has been installed. The architecture of the monitoring system is based on sensing systems from different manufacturers, but having in common a USB digital output. The data communication, as well as the developed softare codes to ensure the data processing, collection and display are also presented.

The most important types of interactions of occupants with the building façades or control systems are defined. The models available to integrate human behavior on simulations are explained. Results of the different studies, both field works and simulations, are presented and discussed. The corrective measures to improve the indoor environmental quality are explained, as well as the strategies to promote more environmental friendly behaviors.

Besides the positive impacts on environment and the reduction of exploitation coss of buildings, the environmental certification of buildings may contribute to rise their value. The methods to translate the environmental performance into finantial benefits are discussed in this presentation.