Percent Diff
Eq 4.2.7-5 And the total fuel consumption is:
4.2.7.4. Thermal model
Total Thermal losses (wasted energy):
Qwaste = NDEGS PDEGS (100 - ηel) / ηel Eq 4.2.7-7
4.2.7.5.
External data file
Type 120 optionally reads a fuel consumption curve from a data file. An example is provided in "Examples\Data Files". The data file should have the following information:
<Nb of DEGS>
<No of the DEGS>, <Name of DEGS>
<Rated power> <coefficient A [l/h]> <coefficient B [l/h]>
EXAMPLE 3
1,Generic Model Reference Curve (40 kW) (DEGS2.EES) 40.0 2.0780 9.2521
2,Volvo Penta D 100 B Gen Set (72 kW) (Neumann, 1987) 72.0 4.2419 16.4926
3,MAN Diesel-Motor D 0224 ME (32 kW) (Pryor, 2001) 32.0 1.2945 7.4180
4.2.7.6. References
1. Lloyd C. R. (1999) Assessment of diesel use in remote area power supply. Internal report prepared for the Australian Greenhouse Office, Energy Strategies, Canberra.
2. Adler U., Bauer H., Bazlen W., Dinkler F. and Herwerth M. (Eds) (1986) Automotive Handbook. 2nd edn, Robert Bosch GmbH, Stuttgart.
3. McCarthy R. D. (1982) Mathematical models for the prediction of liquefied-natural-gas densities. Thermophysical Properties Division, National Bureau of Standards, USA.
4.2.8.
Type 175: Power conditioning unit
Type 165 is a mathematical model for a power conditioning unit. The model is based on empirical efficiency curves for electrical converters (DC/DC) or inverters (DC/AC or AC/DC). The empirical relationship used in Type 175 was first proposed by [1] and further improved by [2]. The model is in agreement with related literature [3].
4.2.8.1. Nomenclature
Pin [W] Power entering the conditioner Pout [W] Power leaving the conditioner Ploss [W] Power losses of the conditioner
P0 [W] Idling power
Pn [W] Nominal (rated) power Us [V] Setpoint voltage Uout [V] Output voltage Ri [Ω] Internal resistance
Ripn [V²] Internal resistance constant = Ri Pn
η [-] Electric efficiency
Iout [A] Output current
4.2.8.2. Electrical model
The power conditioner can have either output or Input power as Input for the calculations (output if the system is connected to a load, or Input if the system is connected to an electric power source). MODE=1 indicates that the power source is known, while MODE=2 indicates it is an output.
Power conditioners are devices that can invert DC power to AC power, and/or vice versa, or they function as DC/DCconverters. In a Stand Alone Power Systems (SAPS) consisting of both DC power producing and DC power consuming components, DC/DCconverters are sometimes needed to transfer DC power from one voltage to another. This is particularly true if there is a large mismatch between the I-U characteristics of the various components.
In a SAPS based on a natural energy source, such as solar or wind energy, the system Input power varies continuously with time. The output characteristics of a PV array, wind turbine, or hydro turbine (run off river) have peak power points that depend on solar insolation and cell temperature, wind speeds, and water flow rates, respectively. Therefore, it may be advantageous to use a maximum power point tracker (MPPT) to utilize the Input power source to its fullest capability [3].
The power loss (Ploss) for a power conditioner is mainly dependent on the electrical current running through it. Laukamp, [1], proposed a three-parameter expression to describe the power loss for a power conditioner:
Ploss = Pin - Pout Eq 4.2.8-1
Pin - Pout = P0 + ( US / Uout ) Pout + (Ripn / Uout2) Pout2 Eq 4.2.8-2 A convenient relationship between the Input power Pin and output power Pout can be derived by
normalizing Eq 4.2.8-2 with respect to the nominal (maximum) power Pn of the power conditioner: Pin Pnom = P0 Pnom + 1 + Us Uout · Pout Pnom + Ripn Uout2 · Pnom · Pout Pnom 2 Eq 4.2.8-3
In Type 175, either the Input power Pin or the output power Pout can be specified as Inputs. If Pout is Input, then Eq 4.2.8-3 is used directly. However, if Pin is Input, then an expression analytically derived from Eqn.3 is used. This makes the model numerically very robust. The efficiency of the power conditioner is simply:
Electric efficiency: η = PPout in Eq 4.2.8-4 Current ouput: Iout = Pout Uout Eq 4.2.8-5
4.2.8.3. Additional information
Type 175 is also described in an EES-based executable program distributed with TRNSYS 16: %TRNSYS16%\Documentation\HydrogenSystemsDocumentation.exe
4.2.8.4. References
1. Laukamp H. (1988) Inverter for photovoltaic systems (in German). User-written TRNSYS source code., FraunhoferInstitute für Solare Energiesysteme, Freiburg im Breisgau, Germany. 2. Ulleberg Ø. (1998) Stand-Alone Power Systems for the Future: Optimal Design, Operation &
Control of Solar-Hydrogen Energy Systems. PhD thesis, Norwegian University of Science and Technology, Trondheim.
3. Snyman D. B. and Enslin J. H. R. (1993) An experimental evaluation of MPPT converter topologies for PV installations. Renewable Energy 3 (8), 841-848.
4.2.9.
Type 180: Photovoltaic array (with data file)
Type180 is a mathematical model for a photovoltaic (PV) generator, based on an equivalent circuit of a one-diode model, also known as the 5-parameter model (see Figure 4.2.9–1). The model is primarily intended for PV-arrays consisting of silicon cells, but can also be used for other types of materials. The electrical model used in Type180 is described in [1]. A dynamic thermal model has also been included [2,3].
V
I
Rs
ID
IL
Rsh
Figure 4.2.9–1: PV cell equivalent electrical circuit (one diode model)
The non-linear equations in section 4.2.9.6 can be solved for any cell temperature Tcell and irradiance GT. In the Type180 model this is done numerically by using the Newton-Raphson iteration [4] - for a given voltage U, the model calculates the current I. A maximum power point tracker (MPPT) algorithm which finds the maximum power point automatically is also included in Type180. Since the P-U curve of a PV generator is a unimodal function, a golden section search algorithm [9] can be used to find the maximum power point. This makes the MPPT algorithm in Type180 very robust.
The main difference between Type 180 and Type 94 is that the parameters of the PV array are read in a data file (see section 4.2.9.3).