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XV EUROPEAN CONFERENCE MILANO 7th-8th JUNE 2013 CSG
Latest Technology in Refrigeration and Air Conditioning Under the Auspices of the PRESIDENCY OF THE COUNCIL OF MINISTERS
Retrofitting existing heating systems with water-water heat pumps fed by
low temperature water networks
Marco Masoero, Chiara Silvi, Dipartimento Energia, Politecnico di Torino
Gianfranco Pellegrini, AREA Science Park, Trieste
2
Concept• Water-water high temperature heat pumps (Tsupply ≥ 60°C) may
replace gas / oil fueled boilers in conventional radiator heating systems, which are common in Italian residential buildings.
• The low temperature heat source is water distributed with a district pipework (LTDH Low Temperature District Heating).
• The district pipework is easier to install and less invasive than a standard high temperature DH one, since pipe insulation is not needed.
• A heat exchanger connects the primary network (LTDH) with the evaporator of the heat pump.
• The HP condenser produces hot water for space heating and centralised SHW production (if present)
Low temperature heat source
Low temperature water may be provided by:•sea, lakes, rivers, canals; •unused pits; •shallow table water; •urban or industrial water mains; •sewage systems;•……..
3
The heat pump (TINA 115 kW)
4
Heat pump characteristics
• Two stage vapor compression cycle (working fluid R 600 (n-Butane)
Property Value
Thermal power output 115 kW
Water supply temperature 60 – 80 °C
COP 3.9 – 3.0
Minimum water temperature 7°C
Water flow rate 1.7 – 6.0 L/s
Maximum electrical input 40 kW
5
6
Central plant for space heating and SHW production
70°C
HT HP12°C
7°C
80°C
7
Supply from water mains
1" 1
/4
1" 1/4
1" 1/4
1" 1/4
Supply from shallow table water
8
Analysis
GENERATORI TERMODINAMICIAndamento degli investimenti
0
250.000
500.000
750.000
1.000.000
1.250.000
1.500.000
1.750.000
2.000.000
2.250.000
2.500.000
2.750.000
3.000.000
10 20 30 40 50 60 70 80 90 100
Numero di generatori da installare(Generatore tipo da 100 kWt cadauno - Edificio tipo da 30.000 mc)
Inv
es
tim
en
to [
€]
Costo centrali termiche
Costo allacciamenti
Costo rete
Investments vs. number of heat pumps
Yearly expense
GENERATORI TERMODINAMICIAnalisi economica
0
100.000
200.000
300.000
400.000
500.000
600.000
700.000
800.000
900.000
1.000.000
10 20 30 40 50 60 70 80 90 100
Numero di generatori da installare(Generatore tipo da 100 kWt cadauno - Edif icio tipo da 30.000 mc)
Sp
esa
ann
ua
risc
ald
amen
to [
€]
Spesa annua attuale
Spesa annua prevista
GENERATORI TERMODINAMICIAnalisi energetica - TEP risparmiati
0
200
400
600
800
1.000
1.200
1.400
10 20 30 40 50 60 70 80 90 100
Numero di generatori da installare(Generatore tipo da 100 kWt cadauno - Edificio tipo da 30.000 mc)
TE
P [
TE
P/a
nn
o]
Stato di fatto
Stato di progetto
TOE saved yearly
GENERATORI TERMODINAMICI
Analisi ambientale - riduzione emissioni globali di CO2
0
500
1.000
1.500
2.000
2.500
3.000
10 20 30 40 50 60 70 80 90 100
Numero di generatori da installare(Generatore tipo da 100 kWt cadauno - Edifi cio tipo da 30.000 mc)
Stato di fatto
Stato di progetto
Emission reduction of CO2
GENERATORI TERMODINAMICI
Analisi ambientale - riduzione emissioni globali di NOx
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
4,00
10 20 30 40 50 60 70 80 90 100
Numero di generatori da installare
(Generatore tipo da 100 kWt cadauno - Edifi cio tipo da 30.000 mc)
Stato di fatto
Stato di progetto
Emission reduction of NOx
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Conclusions
• Reduction of urban pollution associated to combustion heating plants.
• Simple retrofit: boilers are replaced by heat pumps without modifying the heating system.
• Initial costs are balanced by reduction in energy bills and maintenance cost (35÷60%).
• Payback time for Italy, based on climate and energy rates: per l’Italia: 3÷5 years, depending on fuel and type of installation.
• Solution applicable both to the existing stock (residential, historical buildings, schools, hospitals, commercial, industrial, etc.).
• At least 70% of energy input is renewable.
