Category EuroSun2008-10

Load profiles

For the simulations daily and weekly load variations for the DHW with hourly resolution were created in order to separate between the ambient temperature dependant SH and independently varying DHW loads. To achieve realistic load profiles, they were created based on measurements from operational plants.

1.1. Measured load profiles

Measured hourly load data was obtained from six plants of various sizes. Measured monthly total loads were obtained from 18 plants of various sizes. It was found that the studied load profiles are basically of the same shape, i. e. mostly SH with a comparatively small summer loads (DHW and partly or mostly distribution losses), lower than 15% of peak load.

1.2. Load profiles for simulation studies

Based on the measured data representative generic load profiles we...

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Boundary conditions


The simulation study is based on a single family house with a living area of 128 m2 located in Wurzburg, Germany. The roof area where the collectors are mounted is facing south with an inclination of 45o. The space heating demand of the building conforms to the current legal energy saving regulations (EnEV) and amounts to 71 kWh/ (m2 a) respectively 9090 kWh/a. The heating control is automatically adjusted to the outside temperature with a maximum flow/return temperature of 35/25°C. The heat demand for hot water amounts to 2945 kWh/a for a daily use of 200 litres at 45°C. The total heat demand (thermal requirement) for hot water preparation and space heating amounts to 12680 kWh/a, assuming heat losses of a conventional hot water store of 645 kWh/a...

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Solar Combi+: Identification of most promising markets and promotion of standardised. system configurations for small scale solar heating & cooling applications

A. Troi[9]*, Y. Vougiouklakis2, E. Korma2, D. Jahnig3, E. Wiemken4, G. Franchini5, D.
Mugnier6, B. Egilegor7, P. Melograno1, W. Sparber1

1 EURAC, Institute for Renewable Energy, Viale Druso, 1, 39100 Bolzano, Italy
2 CRES, Centre for Renewable Energy Systems, 19th km Marathonos Ave.,190 09 Pikermi, Greece
3 AEE INTEC, Institute for Sustainable Technolgies, Feldgasse 19, 8200 Gleisdorf, Austria
4 Fraunhofer Institut fur Solare Energiesysteme (ISE), Heidenhofstrahe 2, 79110 Freiburg, Germany
5 Universita degli studi di Bergamo, viale Marconi, 5, 24044 Dalmine (BG), Italy
6 TECSOL, 105 rue Alfred Kastler, 66000 Perpignan, France
7 Ikerlan Technological Research Centre, Juan de la Cierva, 1, 01510 Minano (Alava), Spain
* Corresponding Author, alexandra. troi@eurac. edu


In autumn 2007 the Euro...

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Monitoring results in the demonstration house

Fig.4 shows the hydraulic schemes of the old and the new heating system with the heat meters which are red marked and named “Fdxx” and listed in Table 1.

to 10th October, Lisbon – Portugal *

Old heating system:

New solar combisystem:

Fd1: “Solar Gain”

Fd2: “Boiler”

Fd15: “Domestic Hot Water-Heating”

Fd16: “Space Heating”

Fd3: “Space Heating”

Fd18: “Domestic Hot Water-Circulation”

Fd5: “Domestic Hot Water-Circulation”

Fd19: “Domestic Hot Water-Consumption”

Fd4: “Domestic Hot Water-Consumption”

Gas meter: “Natural Gas Consumption”

Gas meter: “Natural Gas Consumption”

Electricity meter: “Electricity Consumption”

Electricity meter: “Electricity Consumption”


~^ Collector —...

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Current Study

The current study is an extension to the previous experimental study, however, the objective of the current study is to determine how the heat pump unit responds to a wide range of input temperatures. As well, a goal of the current study is to determine if the steady-state model previously developed in the first study can accurately predict the dynamic operation of the system. A varying power input to the heaters was applied ranging from 750 – 1500 W in a sinusoidal fashion, similar to that of a daily solar heat input. The fluid temperatures delivered to the evaporator varied between 15 and 37oC corresponding to the power output of the heaters...

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Parameter Variations

image246 image247

A closer look on the results of dimensioning the base case leads to a comprehensive knowledge about the MaxLean system behaviour and the advantages of the concept. To gain insight into the influence the components have on the optimised system, a number of parameter variations were performed. For each variation a new optimisation procedure was carried out leading to different curves in the cost/savings diagram. Figure 3 gives an overview of the parameters varied and the results of the optimisation runs.


* base case

• best points

Fig. 3. Cost benefit diagrams of the parameter variations. The triangular dots in the respective charts
represent the dimensioning of the base case. The circular dots are the associated best points, generated with
the varied parameters...

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Simulated system

There are several possible ways to connect a solar thermal plant to a DH network, with no proven general optimal system layout. The chosen system design principle is shown in fig 2., where the storage tank is connected in parallel with boilers. The control system keeps the outlet temperature from the collector array always above the required DH supply temperature by varying the collector loop mass flow rate. This control strategy is needed, if one wants to be able to completely turn off the boilers for a period during summer.

2.1. Studied system sizings

The main sizing criteria was to be able to turn off boiler(s) for some period during the summer, as this would both save maintenance costs and reduce boiler operation at low efficiency...

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Control of a domestic hot water solar heater with weather forecast

Mihai Radulescu1* and Aude Lepeltier2

1 EDF R&D Site des Renardieres, Dept EnerBat, Avenue des Renardieres – Ecuelles, 77818 Moret sur Loing
2 Ecole des Mines de Douai, 941 rue Charles Bourseul, BP 10838, 59508 Douai Cedex
* Corresponding author, mihai. radulescu@edf. fr


This paper presents the efficiency improvement and electricity economy obtained by introducing an advanced control of a hot water solar heater (HWSH) using a weather forecast. In order to quantify the energy gain of the advanced control a numerical model was built for the storage tank. This model takes into account all inlet and outlet energy fluxes and it’s able to determine the temperature inside the tank at any moment and height...

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