Heat Pump Design – Heat Pump Simulation
80/20 Engineering provides a range of capabilities to assist with heat pump design, simulation and optimization. The key component of both air source heat pumps (ASHP) and ground source heat pumps (GSHP) is the compressor. These are usually scroll compressors, reciprocating compressors or screw compressors, although other compressor types are sometimes used.
Simerics-MP+ includes a specific meshing template for scroll compressors. This automatically handles the mesh contortions necessary to model the unusual motion of these devices. Gao, Ding and Jiang describe the modelling of these in their paper* entitled “3D Transient CFD Simulation of Scroll Compressors with the Tip Seal”. Simerics-MP+ customers have performed many other scroll compressor studies on a commercial in confidence basis.
Simerics-MP+ valve templates are used for modelling reciprocating compressors. One example is contained in the paper* “A 3-D Transient CFD Model of a Reciprocating Piston Compressor with Dynamic Port Flip Valves” by Sujan Dhar, Hui Ding and Jônatas Lacerda.
For twin screw compressors 80/20 Engineering offers both design using SCORG and simulation using Simerics-MP+. SCORG can create appropriate screw profiles using empirical design rules. It then outputs simulation ready meshes that Simerics-MP+ can utilize with its fast, accurate and robust solvers. One of the many technical papers published about this integration is “Numerical Simulation of Unsteady Flow in a Scroll Compressor” by Haiyang Gao and Yu Jiang*.
ASHP’s often also include a large fan to cool the external heat exchanger. CFturbo is a design tool that is commonly used to design axial and radial fans based on a prescribed pressure head and air flow rate. Using well tested design rules it will generate the necessary blade profiles for the fan. It closely integrates with many CFD tools including Simerics-MP. This allows for the fast virtual testing of proposed designs to help optimize the performance of the device.
The various heat exchanger components in heat pump systems are easily simulated using the Simerics CFD packages. Fast automatic meshing and rapid solution turnaround allows for the explicit modelling of various types of heat exchanger. Many slower CFD solvers would encourage the use of approximation techniques. Heat exchanger examples are included in other pages of this website. Simerics also includes some of those common approximation methods for where the engineer is trying to model a full system.
Other system components including the control valve are also commonly simulated using Simerics. Valves in fixed positions are rapidly modelled in Simerics-MP while Simerics-MP+ allows for the dynamic interaction of valve motions with fluid flows. This could allow for the early detection of water hammer type phenomena in pipe systems. Valve flow optimization studies are also performed using the CAESES upfront design tool which is also supplied and supported by 80/20 Engineering.
80/20 Engineering is the UK support centre for Simerics, CFturbo, CAESES and a referral partner to SCORG. We can therefore offer implementation packages for all these engineering software packages. Our engineers are also on hand to offer consultancy services to help with the design and development of heat pumps.
* Please also contact us if you would like to receive a copy of the papers mentioned above: firstname.lastname@example.org
Pressure inside a reciprocating compressor at different points during one cycle of the piston movement. The discharge and the suction valve solids are both shown in yellow
Instantaneous Pressure field at 180 degrees rotation position: (a) not including tip seal volumes (b) including tip seal volumes.
Heat Exchanger Design