Heat transfer systems contain many sources of nonlinearity including temperature dependent material properties, radiation boundary conditions, and internal source terms. Despite progress in numerical simulations, producing accurate models that can predict these complex behaviors are still encumbered by lengthy processing times. Accurate models can be produced quickly by utilizing projection Reduced Order Modeling (ROM) techniques. For discretized systems, the Singular Value Decomposition technique is the preferred approach but has had limited success on treating nonlinearities. In this research, the treatment of nonlinear temperature dependent material properties was incorporated into a ROM. Additional sources of nonlinearities such as radiation boundary conditions, temperature dependent source heating terms, and complex geometry were also integrated. From the results, low conductivity, highly nonlinear material properties were predicted by the ROM within 1% of full order models, and additional nonlinearities were predicted within 8%. A study was then done to identify initial snapshots for use in developing a ROM that can accurately predict results across a wide range of inputs. From this, a step function was identified as being the most accurate and computationally efficient. The ROM was further investigated by a discretization study to assess computational gains in both 1D and 3D models as a function of mesh density. The lower mesh densities in the 1D and 3D ROMs resulted in moderate computational times (up to 40 times faster). However, highly discretized systems such as 5000 nodes in 1D and 125000 nodes in 3D resulted in computational gains on the order of 2000 to 3000 times faster than the full order model. / Ph. D.

The thesis is focused on the design of the new heat source of the existing building. The first part deals with the heat sources and fuels used in the Czech Republic. The second part includes design of three variants of heat sources: gas boilers, cogeneration unit with the electric boilers and cogeneration unit with gas boilers. The individual variations are also evaluated in terms of user comfort, space requirements or economy of operation. The third part includes measurement and evaluation of internal environment of the dining hall.

The master's thesis is focused on heat pumps as a device using sources of a low-potential heat for building's heating. There are individual types of these devices characterized by a principle of operation and used media. Main focus of this thesis is a design of a compact air-water heat pump for the company PZP HEATING a.s. consisting of a cooling circulation’s design and individual components of this circulation. Finally there is a proposal of the heat pump’s case presented at the end of this work.