Balancing Energy Demand with Buildings
Starting point / motivation
The increasingly spread construction of innovative buildings and according technologies results in a shift from the use of fossil energy resources to the indirect use of electrical equipment such as compression heat pumps, ventilation etc. to meet the primary energy needs. This leads to higher base loads and partially to pronounced peak loads, which alter the load profiles of the buildings. Furthermore, there is the trend, that the number of so-called "Energy-Plus-Buildings" is increasing . This results in a decentralization of the energy production, which is thereby dependent on the energy supply, and in a poorer predictability due to the complexity of the distribution and supply networks. Accompanying to this development it is therefore necessary to develop new concepts for the operation and application of the building control to reduce the maximal energy consumption to ensure a stable and high-quality power supply.
Contents and Objectives
This project addresses the issue of the possible extent of smoothing of load profiles (Peak Shaving) of functional buildings by new automation techniques for the thermal and the electrical operation and thus offering room for a more efficient automation. An assessment of the possible saving of energy and the subsequent CO2-reduction by the improved load profile was carried out. The saving approach is based on two possibilities for the use of energy management. On the one hand, synergies can occur when assessing buildings which use renewable energy regarding a better coordination and optimization of energy supply and demand. On the other hand, the necessity of using power supplies from peak-load electricity generation plants can be minimized by load shifting and an intelligent storage management. The building or the group of buildings is thereby upgraded to an "active consumer" within the power grid, thus contributing to a CO2-reduction by a substitution of peak demands by flexible storage processes.
The implementation of these innovative automation techniques will be carried out with targeted building components, which are already widely applied in modern buildings. These components comprise thermo active building systems, cooling and heating buffer storage, the corresponding building automation system and the strategically well-placed use of time-independent energy consumers.
In the course of the project BED different cases were investigated on the basis of thermal simulations with the aim of shifting the thermal and electrical energy taking into account the level of comfort of people. By means of adaptive calculation algorithms the data can be attributed to specific conditions. By the combination of self-learning calculation algorithms and the corresponding condition it is not only possible to adapt the actions on the conditions, but also to constantly improve the processing of the data.
The result of this project is an intelligent and self-learning automation strategy which can be applied in currently used automation techniques and which serves as interface between an optimal usage of storage techniques, the optimal integration of buildings in regenerative energy systems and the structures of network operators and power suppliers.
The potential of office buildings according to the ‘Passivhausstandard’ often finds the focus of discussion in the building and energy sector. On one hand side the passive thermal performance of this kind of buildings shows a good possibility for load management, on the other hand the flexibility is reduced due to the optimized and reduced demand of energy for HVAC appliances. However, the results of this project point out some potential in load management. Even in a well driven office building is a margin in flexible loads to participate to the grid. In this case the shift of the heating demand and the air conditioning system were identified as promising. However, the former one is the appliance which has the more important role. Even with disadvantageous boundary conditions a load shedding of the heating supply of 24 h were possible without violating the comfort parameters.
For the load shift with the air condition system more restrictive boundary conditions have to be taken into account. The characteristic of the CO2 concentration often shows high peaks in some critical zones of a whole building. Restricted to these areas a complete shedding of the load is hardly ever possible.
In the case of the ENERGYbase these critical zones were identified for the lecture rooms of the FH Technikum Wien and the meeting rooms situated in the office areas. One can see that for shifting the load of the air conditioning system, knowledge of the critical zones concerning the state of use is necessary. Although, using the air conditioning system for load management is possible, much more complex boundary conditions have to be taken into account compared to load management using the heat supply.
Dipl.-Ing. (FH) Christian Hettfleisch
AIT - Austrian Institute of Technology GmbH
Project or cooperation partner
- Dipl.-Ing. Dr. techn. Friederich Kupzog
ICT TU Wien
- DI Klaus Pollhammer
ICT TU Wien