Energy and Buildings 75 (2014) 523–530 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me page: www.elsevier.com/locate/enbuild Investigation of Heat Pump Condenser Performance in Heating Process of Buildings using a Steady-State Mathematical Model Jozsef Nyers a,∗ , Arpad Nyers b a Subotica Tech. Serbia, Obuda University, Budapest, Hungary b Subotica Tech. Serbia, Tera Term co. Subotica, Serbia a r t i c l e i n f o Article history: Received 18 December 2013 Received in revised form 6 February 2014 Accepted 20 February 2014 Keywords: Condenser Heat pump Appropriate Circulation pump Mathematical model Lumped parameters a b s t r a c t The general aim of the paper is the wide-range analysis of heat pump plate condenser performance depending on external impacts. The external impacts are the inlet temperature of hot water, the hydraulic resistance of the hot water circuit, the power of circulation pump and the surface of condenser. The addi- tional goal is to ﬁnd the appropriate power of circulation pump to obtain the near maximum condenser performance as a function of resistance to ﬂow in the hot water circuit and dimension of condenser. The performance of condenser is the quantity of heat exchanged inside the condenser between the refriger- ant and the hot water. The analysis of performance and appropriate power is done using the non-linear lumped parameter mathematical model. The mathematical model includes equations of heat transfer between the hot water and the refrigerant inside the condenser, the power of circulation pump and the hydraulic resistance in hot water circuit. The mathematical model of the condenser is divided into a section of superheated steam cooling and a section of saturation steam condensation of refrigerant. In order to solve the mathematical model, which comprises of nonlinear algebraic equation system, the Newton–Taylor linearization and Gauss elimination methods were applied. © 2014 Elsevier B.V. All rights reserved. 1. Introduction In scientiﬁc journals a lot of articles deal with the research of heat pumps in stationary regime using various lumped parameter mathematical models. Most of the mathematical models con- tain the main four components including the condenser, as well. Research of all reviewed articles focused on the behavior of a complete system rather than individual components, such as the condenser. Hatef and Madani et al. [1] examined the heating sys- tem with a heat pump in terms of capacity control for the entire heating season. For the study they developed a lumped parame- ter steady-state mathematical model for stationary regime. In the model the mathematical description of condenser is based on the energy and mass conservation. Enthalpy as the state parameter has been applied instead of the temperature, Kinab et al. [2]. Their aim was the investigation of optimal seasonal performance of reversible heat pumps. The mathematical model of condenser is created in the exponential series based on the data of existing condenser. The behavior of condenser was not specially investigated. ∗ Corresponding author. Tel.: +381 24 687175; fax: +381 24 687175. E-mail addresses: jnyers@vts.su.ac.rs, nyarp@yahoo.com (J. Nyers). A smaller number of articles dealt with the study of condenser’s behavior as a component of heat pump. The reviewed articles mainly investigated the processes in the condenser in terms of heat transfer. Qiao et al. [3] developed a new mathematical model for stationary heat transfer within the plate heat exchanger, which can be used for the condenser as well. The mathematical model is two-dimensional with distributed parameters. The ﬁnite difference scheme is used for discretization. The behavior of condenser was investigated in terms of the internal heat transfer. They investigated the inﬂuence of constructive details on the heat transfer within the plate condenser. The external inﬂuences on the condenser perfor- mance were not discussed. Cesar Pacio et al. [4] carried out review of published papers related to the plate evaporator and condenser, applied in refrigeration systems. The work classiﬁed the mathemat- ical models and the procedures for solving the model. They gave an overview of possible negligence in the mathematical models. The work does not deal with the investigations of heat transfer within the evaporator and condenser as a function of external impacts. A good selection of heat transfer coefﬁcient of refrigerant as well as of the hot water is very important. In fact, the accuracy of results obtained by simulation mainly depended on the quality of heat transfer coefﬁcients. There are thousands of authors and titles that deal with this topic; however, the problem is of a large dissipation of results obtained from the proposed models. This problem was http://dx.doi.org/10.1016/j.enbuild.2014.02.046 0378-7788/© 2014 Elsevier B.V. All rights reserved.