GUIDE FOR CHOOSING AN ACCUMULATOR TANK

Preliminary version 0.1 13.3.2006

TABLE OF CONTENTS

1 OVERVIEW………………………………………………………….. 5 2 OPERATING PRINCIPLE..………………………………………… 6 3 DIMENSIONS ………………………………………………………. 8 4 PRODUCT RANGE …………………………………………………. 10 5 SPATIAL REQUIREMENTS ……………………………………….. 12 6 TECHNICAL DRAWINGS …………………………………………. 13

1 OVERVIEW The Guide for Choosing an Accumulator tank is meant to be used as a source of information for both designers of heating systems and private customers, who are intending to acquire a hot accumulator tank. This guide introduces the operating principles of the accumulator tank and its dimensions along with the technical characteristics and spatial requirements of different models. Akvaterm Oy already has over 20 years of experience in the manufacture of hot accumulator tanks. The manufacturing process is governed by a quality system monitored and awarded by Inspecta Oy, and the pressure safety of the tank is ensured through pressure testing in accordance with the Pressure Vessel Directive. For more information on accumulator tanks please visit Akvaterms web site at www.akvaterm.fi.

AKVATERM OY

Jänismaantie 12 67800 Kokkola

FINLAND Tel. +358 (0) 6 824 4200 Fax + 358 (0) 6 824 4224

info@akvaterm.fi www.akvaterm.fi

2 OPERATING PRINCIPLE Storing heat in water is an easy and practical way to store energy.

• The accumulator tank stores and levels the energy from the energy source. • Energy can be generated the most efficient way or when it is at its cheapest. • Heating equipment can be loaded at a high and steady level to ensure the highest operating

efficiency and the lowest environmental emissions. • The accumulator tank allows reaching a pleasantly low surface temperature for the heat

distributor, a comfortable room temperature and copious amounts of hot water for domestic use when using the domestic hot water coil.

• A properly dimensioned accumulator tank does not bind the user to time and place. The accumulator tank allows you freedom.

The accumulator tank is suitable for use in conjunction with a water-based central heating system, but it can also be used in conjunction with air heating systems. As the accumulator tank is suitable for use with several different heat sources, its use allows for the simultaneous use of several heat sources and allows you to alter the energy source in the future. Most heating methods require connecting the accumulator tank to the heating system. The hot accumulator tank is useful also with sources that function independent of an accumulator tank. For example, used in conjunction with oil-based heating systems, the accumulator tank reduces the number of start-ups for the burner and increases the total operating efficiency of the system.

Electricity or geothermal heat with storage

Log boiler

Solar power (also additional energy sources needed)

3 DIMENSIONS 3.1 Dimensions of the Accumulator tank

The size of the accumulator tank is determined by the following factors, for example:

• The output requirement of the dwelling / output and efficiency of the heat source • Water consumption (family size) • Space • Operating conditions • Temperature of the heating circuit • Geographical location

The following examples of dimensions are for guideline only. More accurate dimensions can be requested from HVAC professionals.

3.1.1 Electrical Heating

The heating energy required for full storage heating systems is produced during night time, when the price of electricity is at its lowest. Full storage heating systems nevertheless require high electrical output and a large accumulator tank. Partial storage heating systems generate the majority (80-90%) of the annual energy required for heating the rooms and the water in the night, but the remainder is produced during the day or via an additional heat source. Daytime heating is required when the outside temperature drops below -10°C. Partial storage heating systems enable the use of a significantly smaller accumulator tank and a lower output in comparison with a full storage heating system. The accumulator tank is dimensioned for an output of 40 W/m2 (used in Finland), which covers 90% of the required overall output. This means that it is based on partial storage.

500

1000

1500

2000

2500

3000

3500

4000

45 70 90 135 182 275 364

Dwelling size (square meter)

Acc

umul

ator

size

(litr

es)

Dimensions

of the accumulator

tank

Output Energy conveyance cap-acity in the day

time /h (16h)

Combined cap-acity of electric resistors used in the night

Size of the dwelling

Main fuse / connection

500 l 29 kWh 1,8 kW 5,5 kW 45 m2 25 A 750 l 44 kWh 2,8 kW 8,5 kW 70 m2 25 A

1,000 l 58 kWh 3,6 kW 11,0 kW 90 m2 25 A 1,500 l 87 kWh 5,4 kW 16,0 kW 135 m2 25 A 2,000 l 116 kWh 7,3 kW 22,0 kW 182 m2 35 A 3,000 l 174 kWh 11,0 kW 33,0 kW 275 m2 50 A For example, dwelling sized 90m2 The required amount of heating is: 90m2 · 40 W/m2 = 3600 W =3,6kW Output: 16h · 3,6kW ≈ 58kWh .

This determines the capacity of the required accumulator tank, which for a dwelling sized 90m2 is 1,000 l.

A rough guideline to measuring the combined capacity of electric resistors used in the night: 3,6kW · 24h ≈ 86,4kWh 86,4kWh/8h ≈ 11,0kW

3.1.2 Other forms of heating

Dimensioning according to the instructions supplied by the supplier/manufacturer. 3.2 Domestic Hot Water Coil

In the Akva and Akvasan models, the flow is 35 l/min and in the Akvantti model, the standard flow is 45 l/min.

Standard coils Output kW

Flow l/min

AKVA 35 LK 90 35 AKVA 60 LK 150 60 AKVA 80 LK 205 80 AKVA 100 LK 255 100 AKVA 120 LK 310 120

We recommend the installation of a 35 l/min preheating coil in the lower hatch in order to considerably increase the amount of domestic hot water available and to improve the heat layering of the accumulator tank.

3.3 Expansion vessel The capacity of the expansion vessel should be:

• 10% of the entire water capacity when using electricity, wood and peat • 5% of the entire water capacity when using oil and geothermal heat

4 PRODUCT RANGE The Akvaterm product range contains a model for all purposes. When the required dimensions are known, the accumulator tank characteristics should be reviewed with regards to the technical space, as the accumulator tank model is largely determined by the height of the technical space and the width of the doorways. Small spaces and narrow doorways are catered for by the ranges AKVASAN and AKVANTTI. Should the location of the accumulator tank be under design, the AKVA standard accumulator tank is recommended. It should be brought to the technical space during construction phase at latest.

AKVA Standard Accumulator tank

Is recommended as the primary alternative. Insulation is 100 mm seamless polyurethane. The upper hatch has a standard domestic hot water coil and a domestic hot water pre-heating coil, a solar heat coil, the heat collector exchanger etc. can be placed in the lower hatch. There are in-built guide pipes that ensure the proper layering of heat. Upon order, it is possible to deliver an un-insulated accumulator tank, an accumulator tank that has

been painted with corrosion protector paint or an accumulator tank equipped with detached insulation.

Dimensions, AKVA standard hot accumulator tanks Model Capacity (l) Diameter

(mm) Height (mm)

Weight (kg)

Resistor Units

AKVA 300 EK 300 710 1,900 130 2 AKVA 500 EK 500 800 1,950 155 2 AKVA 750 EK 750 950 2,050 200 2 AKVA 1000 EK 1,000 1,050 2,100 230 2 AKVA 1500 EK 1,500 1,250 2,150 280 3 AKVA 2000 EK 2,000 1,400 2,200 330 4 AKVA 2500 EK 2,500 1,500 2,250 360 4 AKVA 3000 EK 3,000 1,600 2,250 400 4 AKVA 4000 EK 4,000 1,800 2,350 480 6 AKVASAN Retrofitting Accumulator tank

This model has been developed for constrained spaces and narrow openings. Its diameter is only 800 mm. The efficient cylinder format has been retained, and the insulation is the same as in the standard accumulator tanks, but its strength is 50 mm due to the smaller surface area. The EK-models are equipped with a domestic hot water coil and both day time and night time resistor units. When further equipped with

an electric resistor, its characteristics make it an excellent domestic hot water heater. When only domestic hot water is required, for example in the summer, the E-model can be disconnected.

Dimensions, AKVASAN repair accumulator tank Model Capacity (l) Diameter

(mm) Height (mm)

Weight (kg)

Resistor Units

AKVASAN 0,5 EK 500 795 1,480 130 2 AKVASAN 0,5 E 500 795 1,480 120 1 AKVASAN 0,7 EK 700 795 1,980 160 2 AKVASAN 0,7 E 700 795 1,980 150 1 The E-models do not contain a domestic hot water coil.

AKVANTTI Accumulator tank

The entry dimensions are only 800 mm. Available in capacities 1400 litres, 2000 litres and 2400 litres. The most efficient domestic hot water coil in the market (45 l/min), available also without the domestic hot water coil.

Dimensions, AKVANTTI Accumulator tank Model Capacity

(l) Diameter

(mm) Height (mm)

Weight (kg)

Resistor Units

AKVANTTI 1400 EK 1,400 800 1,650 1,630 3 AKVANTTI 1400 E 1,400 800 1,650 1,630 3 AKVANTTI 2000 EK 2,000 800 1,820 2,060 4 AKVANTTI 2000 E 2,000 800 1,820 2,060 4 AKVANTTI 2400 EK 2,400 800 2,150 2,060 4 AKVANTTI 2400 E 2,400 800 2,150 2,060 4 Accumulator tanks for Apartment Buildings

Suitable, for example, multi-storey buildings and terraced houses. The structural pressure is usually 3 or 4 bar. The capacity, hatches, units, hot water coils etc. according to the customer’s requirements.

Special Accumulator tanks According to the specifications and requirements of the customer. Standard Coils

We are also able to manufacture according to your specifications and images.

Dimensions, Standard Coils

Model Capacity (kW)

Diameter (mm)

Length (mm)

Flow (l/min)

AKVA 35 LK 90 160 750 ¾ 35 AKVA 60 LK 150 160 1,250 1 60 AKVA 80 LK 205 250 900 1 ¼ 80 AKVA 100 LK 255 300 1,000 1 ½ 100 AKVA 120 LK 310 300 1,100 2 120

5 SPATIAL REQUIREMENTS When designing a new technical space, it is useful to make it flexible and sufficiently spacious, as the use of the accumulator tank allows for the alteration of the heat source in the future. For example, when the heat source is a wood-burning stove, the technical space must be large to accommodate the handling of the fuel and the easy removal of the ashes. The location of the actual accumulator tank is not guided by many requirements. The most important thing is to pay attention to the mass of the accumulator tank and the resulting need to reinforce the floor plate. The location should be chosen in such a way that the connection will not be too difficult to make and that the future maintenance will be easy to carry out. The accumulator tank can be located next to the wall, and no more room is required at the top of the tank than what is needed for the connections. The round tank models require a slightly larger space on the floor than the AKVANTTI model. The safety distance of the boiler must be ascertained by contacting the boiler manufacturer. Should the accumulator tank be brought into the space on its side, the diagonal length must be noted when lifting the tank upright. When designing the technical space, it is imperative to take into account the transportation measurements of the accumulator tanks. The AKVASAN and AKVANTTI models are 800 mm wide, so they can be transported in through the doorway. The standard AKVA models are, however, relatively wide, and they cannot often be transported through normal-sized doorways. In these situations the accumulator tank can be taken to the technical space during the construction phase, or alternatively the accumulator tank can, upon order, be manufactured with detached insulation to allow the tank’s diameter to be reduced by up to -200 mm depending on the model.

6 TECHNICAL DRAWINGS

AKVA Standard Accumulator tank

1. Hatch 2. Heating Circuit + Guide Pipes 3. Drain Coupling 4. Thermometer Unit / Thermostat Unit (4 pcs) 5. Accumulator tank Unit + Guide Pipes 6. Electrical Resistor Unit (2-4 pcs) 7. Domestic Hot Water Coil, copper comb, capacity 90 kW, standard 35 l/min, +5…55/75C,

structural pressure 10 bar 8. Pressure Relief / Air Bleeder 9. Polyurethane Insulation 10. Coating, coated galvanised tin plate 11. Tank

maximum pressure 1.5 bar maximum temperature +110 ºC

AKVASAN Repair Accumulator tank

1. Pressure Relief / Air Bleeder 2. Thermometer Unit / Thermostat Unit (2 pcs) 3. Electrical Resistor Unit (2 pcs) 4. Hatch 5. Domestic Hot Water Coil 6. Drain Coupling

maximum pressure 1.5 bar maximum temperature +110 ºC

AKVANTTI Accumulator tank

AKVANTTI 1400 EK Note! Pipe connections from the top of the accumulator tank.

Top Front

1. Entry from the boiler 2. Return into the boiler 3. Exit to the heating circuit 4. Return to the heating circuit 5. Domestic Hot Water Coil 45 l/min 6. Pressure Relief / Air Bleeder 7. Drain Coupling 8. Electrical Resistor Unit 3 pcs 9. Thermostat Unit / Thermometer Unit ]

AKVANTTI 2000 EK, 2400 EK Pipe connections from the side as normal.

1. Tank Unit 2. Domestic Hot Water Coil 45 l/min

2b. Connection for a second coil 3. Thermostat Unit /Thermometer Unit 4. Electrical Resistor Unit (4 pcs) 5. Heating Circuit 6. Drain Coupling 7. Pressure Relief / Air Bleeder

In the AKVANTTI models, the maximum pressure is 1.5 bar and the maximum temperature is +110ºC.