Medicool European Project

A Demonstrative Example of Smart Solar Cooling/Heating System

A. Molina-García

, T. García-Egea

and M. Moreno

Dept. of Electrical Eng, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain

Polytechnic Science Dept, UCAM Universidad Católica San Antonio de Murcia, 30107 Murcia, Spain

Medicool Engineering - Project Manager, HEFAME Group -Santomera-Abanilla 158, 30140 Santomera, Spain

Keywords: Solar Cooling/Heating System, Energy Efficiency, Absorption Chiller, Solar Energy.

Abstract: The main objective of this paper is focused on describing a demonstrative example of a thermal

cooling/heating system. The proposed solution has been implemented in the pharmaceutical distribution

sector, which involves strict and rigid European and national regulations regarding storage temperature

conditions. The developed installation is one of the largest systems ever built in Europe based on solar

cooling/heating technologies. It has a collecting surface of 22,500 m

by using one of the latest

technologies: the Ultra High Vacuum (UHV) collectors. These collectors reduce significantly both

convection and conduction heat losses. The proposed system has two absorption chillers of 675 and 855 kW

respectively. It is expected to provide an annual energy savings estimated of around 795 MWh, only for the

cooling system representing more than 70% of the global energy currently needed for conditioning the

selected warehouse. This solution can be easily extensive towards other industrial sectors in areas with

similar energy characteristics and thermal requirements: large conditioning spaces and buildings with high

cooling/heating power demand during the peak power periods.

1 INTRODUCTION

The decreasing of traditional fossil energy sources,

combined with pollutant emission reduction

agreements, have leaded most developed countries

to propose special tariff systems and tax reductions

for renewable energy solutions. In this upcoming

scenario, new technologies have a remarkable short-

term impact and play an important role towards a

sustainable energy system. As an example, PV

power plants are proposed in (Valentini, 2008) as a

crucial new supply solution. In a similar way, the

useful impact of wind farms on power system

operators is analysed in (Wan, 2005), showing that

load fluctuations even can produce more changes in

the interchange than wind power fluctuations. But

not only supply-side is proposed to be analysed and

modified, in (Kirschen, 2008) is suggested that

consumers should be also considered as a genuine

demand-side capable of making rational decisions,

and not only as a load that needs to be served under

all conditions. However, this desired active

participation in electricity markets by the demand-

side remains minimal, though there is a strong need

to increase customer participation in markets to

enhance system reliability and reduce price volatility

(Kueck, 2001).

With regard to the industrial sector, the

cooling/heating power demand is increasing more

and more in most developed countries. Moreover, in

moderate climates such as most EU member states,

this fact usually produces a dramatic increase of

electricity power demand during hot summer days,

involving undesired increases of both fossil and

nuclear energies and, furthermore, threaten the

stability of electricity grids. These combined

cooling/heating power plants are also becoming

popular in residential and commercial sectors,

aiming to meet desired thermal and electricity

demands.

Since these systems integrate cooling, heating

and power generation capabilities at one site, they

result in potentially lower capital and operating costs

and facilitates ease of maintenance and operation

(Wu, 2006). Another remarkable aspect very related

with the cooling/heating power demand is energy

sustainability. In fact, several political incentives

have been already proposed to emphasize their

163

Molina-García A., García-Egea T. and Moreno M..

Medicool European Project - A Demonstrative Example of Smart Solar Cooling/Heating System.

DOI: 10.5220/0004861001630169

In Proceedings of the 3rd International Conference on Smart Grids and Green IT Systems (SMARTGREENS-2014), pages 163-169

ISBN: 978-989-758-025-3

 2014 SCITEPRESS (Science and Technology Publications, Lda.)

importance into the building sector, taking into

account the existing potential of energy savings as

well as the increased social awareness on energy-

related issues. Indeed, in industrially developed

countries, buildings are contributing with more than

one-third of the total energy consumption, being

major contributors to greenhouse gas emissions.

Consequently, and considering cooling-heating

requirements as well as building aspects, the use of

renewable resources and energy efficiency for space

heating and cooling purposes must be considered as

a relevant topic of interest for the current industrial

sector. In fact, there is a relevant interest in

evaluating and assessing the performance of solar

thermal solutions for those applications, mainly in

countries such as Spain, where the climate offers

appropriate opportunities. For these purposes, solar

refrigeration is more and more recognized as a

priority in developing countries, due to the needs for

minimizing the energy expenditure and

improvement the thermal requirements. In this

context, the use of solar energy for absorption

refrigeration research has been one of the hot issues

along this last decade (Wang, 2000). According to

several authors, refrigeration is particularly

attractive as a solar energy application due to the

near coincidence of peak cooling loads with the

available solar power (Sumathy, 2003). The

absorption system is one of the promising solar

thermal refrigeration methods, and it is

environmentally friendly along with low cost and

low maintenance requirements. Furthermore,

operating costs are 15% less than conventional air

conditioning systems. By installing solar assisted

cooling systems in southern European and

Mediterranean region, about 40–50% of primary

energy can be saved (Balaras, 2007). Under this

framework, the present paper is focused on

describing a demonstrative project financially

supported by the European Union aiming of

providing a real example of sustainable solution for

cooling large storage or commercial spaces, such as

logistic buildings, warehouses, wholesaler… where

temperature requirements are very restrictive.

The rest of the paper is structured as follows:

Section II gives detailed information about the

proposed solution Innovative aspects of the

demonstrative project is discussed in Section III.

Preliminary results are described in Section IV.

Finally, conclusions are given in Section V.

2 SYSTEM DESCRIPTION:

GENERAL OVERVIEW

From the different industrial sector activities, the

pharmaceutical distribution network in Europe

involves by around 1500 operating sites, delivering

more than 6400 hospital pharmacies, 135000

community pharmacies and around 8000 dispensing

doctors. They account for more than 80% of the

pharmaceutical distribution in Europe, delivering

each operating site around 329 pharmacies and 1.11

million people −on average−. This pharmaceutical

distribution system can be also considered as a

current warehouse for most hospitals, which rely on

this system the storage of medicines due to its

efficient and safe delivering systems (set by law, up

to 5 delivers a day and even instant delivery).

Nowadays, there is even a tendency on increasing

the number of those warehouses in Europe, since

logistic companies are getting into the market and

developing the export of medicines by setting

logistic warehouses around Europe. Regarding the

Mediterranean countries, about 630 warehouses are

operating, mainly in Italy, France and Spain, with a

surface of about 2 million m

and generating the

emission of around 62,000 Tons of CO

. In Spain,

there are 192 warehouses with a surface of around

600,000 m

, with a global energy costs of about 3

million €/year and generating about 18,600 Tons of

/year.

With regard to storage temperature conditions,

this industrial sector presents strict and rigid

European and national regulations, being necessary

to follow properly severe temperature requirements.

Indeed, this industrial sector is very sensitive facing

environmental and economic problems. The severe

thermal conditions (25º C ± 2º C and humidity levels

of 60% ±5%) must be fulfilled in every medicine

warehouse located in Europe. These storage

conditions are set by the Directive 2001/83/EC

−amended by Directive 2004/27/EC− and the

subsequent national regulations and codes of good

practices in each country.

In Spain, the Law 29/2006 about guaranties and

rational use of medicines and health products is in

charge of regulating these requirements. However,

this regulation framework is currently fulfilled at

very high economic costs and, in some cases, with

no-efficient technological solutions, involving

remarkable environmental costs. Under this

scenario, the Medicool project gives an alternative

solution to this problem by applying, testing and

validating new industrial processes implemented

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under real conditions. This demonstrative project

gives a real example of the suitability of thermal

cooling-heating solutions under severe temperature

range requirements. It also offers remarkable results

regarding technical adjustments and maintenance

tasks.

The specific characteristics and requirements of

the pharmaceutical warehouses –large conditioning

spaces and buildings with high power demands and

strict temperature range requirements to meet

usually during peak power demand periods− are

very similar to other buildings devoted to different

activities, such as services buildings, malls, sport

centres, food processing and storage industries, or

wine cellars. This conditioning space problem, in

terms of quantitative and qualitative energy demand,

has at this moment a great interest in Europe.

Additionally, there is a remarkable replication

potential of the present project in the rest of the

Mediterranean countries. Indeed, some pharmacy

industries and governments of South-Mediterranean

countries have already expressed their interest in the

results of the project.

As it can be seen in Figure 1, the selected

warehouse for the installation of the present

prototype is located in the Region of Murcia, South-

East of Spain. It has a surface of about 30,000 m

−one of the biggest in Europe−, with a global energy

demand of over 4000 MWh/year, energy costs of

around 140 m€/year and 932 Tons of CO

/year

generated by the whole installations. The solution

provided by this European project involves one of

the largest systems ever built in Europe, based on

solar cooling/heating technologies. It has a

collecting surface of 22,500 m

with the main

objective of reducing the current cooling time

periods that can be varied from 5 hours/day during

the winter to 12 hours/day during the summer

period. On the other hand, it must be pointed out that

this pharmaceutical warehouse is considered as a

general pharmaceutical storage, being used by public

regional hospitals that are not currently available to

be equipped with their own pharmaceutical

warehouses.

The selected pharmaceutical warehouse provides

services to all hospitals and pharmacies in the

Region of Murcia (Spain). This pharmaceutical

distribution is owned by HEFAME, which is one of

the three national leading companies in the sector of

pharmaceutical distribution and owns 6 more

warehouses, mainly in the Mediterranean regions of

Spain (Hefame, 2013). In reference to the storage of

pharmaceutical products, and considering the annual

cycles of outdoor temperature and humidity in the

South-East of Spain, the company presents severe

problems to keep the conditioning space temperature

below 25 ºC. This temperature requirement has been

set by European and national regulations as well as

international codes for pharmaceutical products.

Figure 1: Geographical localization of the demonstrative

project and general information.

Over the past years, some initiatives have been

proposed by different agents to solve the

conditioning large space problem. Indeed, this issue

has been considered as a high priority by the public

administration of the Region of Murcia (Spain),

which has also participated actively in this project

through the Regional Energy Agency of Murcia.

This particular interest is due to there are only a few

projects devoted to assess and implement solar

cooling/heating systems and, most of them propose

smaller systems or prototypes not designed for the

industry. Additionally, there are no examples of

projects in Europe for thermal solar systems larger

than 1MW, being most systems below 100 kW.

3 INNOVATIVE ASPECTS OF

THE MEDICOOL PROJECT

The proposed thermal cooling/heating system works

as follows: the Ultra High Vacuum (UHV) collectors

heat the thermal oil until getting the set-point

temperature (<120º C), adapting the flow to maintain

this value. Afterwards, a heat exchanger is in charge

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of heating the water up to 90 ºC. This water is then

sent to the absorption chillers, using 1 or 2 machines

depending on the thermal power available

(Medicool, 2012), see Figure 2. These machines

cool the water of the cold circuit from the

conventional chillers before water crosses them.

These conventional chillers are responsible for the

last regulation of the temperature. The energy saving

of the system is provided by the cold absorbed by

the solar system that is produced with renewable

energy source (solar). Conventional cooling backup

system and hot water storage are both foreseen to

complement the proposed system. Hot water storage

is part of the system as well; and its associated

benefits are included in the global energy reduction

of around 70% of the total energy. Conventional

cooling system, already installed in the

pharmaceutical warehouse, covers the rest of the

cooling energy needs (30%). The final objective of

this technological solution is to be able to cover the

whole energy requirements without conventional

cooling backup systems, since it would make the

system more efficient in terms of energy

consumption and economically cheaper to install

and maintain. The design of the proposed solution

involves that all storage centres have these

conventional systems already installed and available.

Figure 2: Proposed solution based on solar thermal

cooling-heating system.

In reference to the innovate aspects of the

proposed demonstrative project, new collectors with

the latest technology have been selected, supposing

one of the key elements of the system: the Ultra

High Vacuum (UHV) collectors. These collectors

reduce convection and conduction heat losses. Each

collector is provided with a “Getter” pump that

assures the vacuum. The collectors are composed by

high absorbance (>90%) and low emittance (<7%)

elements, which are exclusive for this kind of

collectors and have not been provided by any other

collectors. This system has been successfully tested

at laboratory and pre-industrial level.

These UHV collectors avoid evaporation

problems of water by heating oil, reaching higher

temperatures with lower pressure, which implies a

simpler valve system. Evaporation is a major

problem for this kind of installations, since the

evaporation of water leads to the breakage of the

collectors. In reference to the use of oil in the

collectors instead of ordinary water, this solution

presents several advantages based on the higher

boiling point of oil: over 355°C at normal

conditions. In the proposed prototype, UHV panels

with a selective treatment of high absorbency and

low emissivity collectors, provided with

concentrators, have been selected. In these

conditions, film temperature can reach higher values

and, at these temperatures, exceptionally good

thermal stability of the transmitting fluid is required.

The proposed mineral oil has bulk temperatures up

to 320°C, and the rates of cracking and oxidation are

very small, providing an efficient fluid heater with

good pump circulation. Moreover, the use of oil

decreases considerably the working pressure values,

reducing then the exigencies and requirements of the

piping, instrumentations and collectors. Due to the

extremely high film temperatures in the collectors,

the use of water would imply high-pressure values to

avoid evaporation processes that may reduce the

performance of the system. Figure 3 shows some

details about the collecting surface as well as the

installation process. Each collector group (126

components) has his own control of temperature on

the oil output, managing each group in order to keep

the collector group within the temperature set value

and avoiding undesired heating or cooling process.

The system is provided with 4 oil circuits connected

in parallel. This layout allows us to give a higher

selectivity in case of breakdown and reduce costs,

due to the use of smaller components.

The system is provided with two absorption

chillers of 675 and 855 kW cooling capacity, instead

of a single one of 1.5 MW cooling capacity. With

both absorption chiller machines is possible to fit the

capacity of cold production according to the real

heat production necessities, being able the system to

use 1 or 2 machines. The use of 2 machines makes

possible a wider range of uses for the installation

and the simultaneous supply of heating and cooling

towards different areas of the building. A PV power

plant has been also integrated as an additional way

to reduce the whole power demand, increasing the

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whole benefits of the solar energy source. In this

case, the PV power plant has 888 kWp nominal

power rate, using PV modules from Schott

monocrystalline 185W (Schott Solar).

Figure 3: Solar thermal cooling-heating system:

Installation process and collecting surfaces.

The innovations of the project are focused on

management issues as well: while ordinary systems

have been provided as an additional support to other

classical refrigeration systems, this demonstrative

prototype constitutes the base of achieving and

maintaining the required temperature conditions.

Furthermore, instead of developing a specific system

devoted to store the excess heat resulting from the

process, the management system is responsible to

assure a permanent and accurate supply of cooling.

This is a major conceptual difference with other

regulation systems: the final regulation goal instead

of an initial one. Gas boilers could be considered a

solution to make the system simpler, but it would

waste most of the saved energy to provide the

corresponding security heat store requirements. The

proposed control system thus optimizes the cold

production with the objective of making the

installation able to speed up a response to

modifications in demand, reliable in its performance

and safe. This fast response is possible due to the

maximum reduction of the used oil fluid.

Accumulators are not used since they need larger

volumes, increasing the size of the installation and

the fixed and operating costs. Moreover, they would

be used only few time periods and make the system

slower in its regulation and considerably less

efficient.

The final solution adopted is a system managing

in real time, where the output temperature in each

closed loop (126 components) is compared with the

set-point value, modifying the input valve if it was

necessary. Subsequently, the temperature is fitted

according to the thermal requirements and the

volume of oil changes with the available solar

power. An additional regulation system is devoted to

control the use of one or two absorption chillers.

This system is in charge of selecting how many

machines must be connected/disconnected according

to the necessities and availability of energy.

Finally, the system also involves sensors to

collect a sort of variables, giving a precise

management of the system with stored data in real

time. This makes possible to take fast and clear

responses. In order to increase the global safety of

the system, steel shutters have been designed to

protect the installation facing abnormal climatic

ranges or system malfunctions. These shutters can

perform automatically and be used as a regulation

tool for the energy output.

4 PRELIMINARY RESULTS

The proposed system is expected to provide an

annual energy savings estimated in around 795

MWh only for the cooling system, which represents

more than 70% of the global energy currently

needed for conditioning the warehouse. It means

about 105 m€, expected to increase according to the

energy price modifications, and reaching up to 1.13

GWh and 150 m€ if the heating energy savings in

the offices were included.

These energy reductions are even more relevant

in daily and seasonally energy demand peaks, being

the system more productive according to the energy

demands are higher. In terms of CO

savings, and

considering a CO

production of 0.233 kg/kWh of

, the proposed thermal cooling/heating system is

expected to save between 185 and 263 Tons of

/year. Other types of emissions that can also be

reduced are the following (per year): 766 Tons of

, 626 Tons of NO

, 4140 cm

of radioactive

residues of low and medium activity, 508 gr of high

radioactive activity residues. At the same time, the

implementation of this solar thermal technology in

other warehouses with the same characteristics and

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the potential of transferability make these amounts

to be much higher. The economic savings have to

take into account indirect issues, as the decreases in

electricity demand on peak power periods, especially

in hot summer days.

Figure 4: Estimated oil and water flow absorption chiller.

675 kW nominal cooling capacity.

Figure 5: Estimated solar radiation data.

Figure 6: Estimated cooling power capacity (kW).

This fact implies a decrease in the use of fossil

and nuclear energy and reduces the threatening to

the stability of electricity grids, allowing energy

managers to design less over-sized electricity grids.

As an example of the estimated absorption chiller

performance, Figure 4 and 5 show respectively the

flow heat exchanger values as a function of the

estimated solar radiation data. As can be seen in

Figure 6, significant power reduction can be

achieved in comparison with conventional solutions

as was previously discussed.

5 CONCLUSIONS

A demonstrative project financially supported by the

European Union aiming of providing a real example

of sustainable solution for cooling large commercial

spaces has been discussed and described in the

present paper. This project, called Medicool,

provides a new solution for the pharmaceutical

distribution sector, which presents strict and rigid

European and national regulations regarding storage

temperature conditions. This solution involves one

of the largest systems ever built in Europe based on

solar cooling/heating technologies, with a collecting

surface of 22,500 m

with the main objective of

reducing 795 MWh only for the cooling system.

This reduction represents more than 70% of the

global energy currently needed for conditioning the

warehouse. It implies about 105 m€, expected to

increase according to the energy price modifications,

and reaching up to 1.13 GWh and 150 m€, if the

heating energy savings in the offices were included.

With regard to innovative aspects of the

proposed system, new collectors with the latest

technology have been selected, supposing one of the

key elements of the system: the Ultra High Vacuum

(UHV) collectors. These collectors reduce

significantly both convection and conduction heat

losses. The proposed system has with two absorption

chillers of 675 and 855 kW each one. For both

absorption chiller machines, an additional control

system is included to fit the capacity of cold

production according to the real heat production

necessities, being able the system to use 1 or 2

machines. The estimated energy reductions are even

more relevant in daily and seasonally energy

demand peaks, being the system more productive

according to the energy demands are higher.

In terms of CO

savings, and considering a CO

production of 0.233 Kg/kWh of CO

, the proposed

thermal cooling/heating system is expected to save

between 185 and 263 Tons of CO

/year. Other types

of emissions that can also be reduced are the

following (per year): 766 Tons of SO

, 626 Tons of

, 4140 cm

of radioactive residues of low and

medium activity, 508 gr of high radioactive activity

residues.

Finally, this solution is easily extensive towards

other economic and industrial sectors in areas that

present similar energy characteristics and thermal

requirements: large conditioning spaces and

buildings with high cooling/heating power demand

during peak power periods.

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168

ACKNOWLEDGEMENTS

The LIFE+ European Program has financially

supported this project. (Ref. LIFE10 ENV/ES/456).

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