ᐅ New Construction System Check KfW55 – Remko Heat Pump / 500L Buffer Tank / Domestic Hot Water Module
Created on: 5 May 2021 20:31
M
marceleisiM
marceleisi5 May 2021 20:31Hello everyone,
My girlfriend and I want to fulfill our dream of owning a home in the form of a semi-detached house built to KFW 55 energy efficiency standards, and we have a few questions regarding our heating system.
First, some basic information:
Currently a 2-person household; planned to be a 4-person household in the future
Basement + 2 full floors + occupied attic
Total house area: 267 m² (2873 sq ft)
Heated area with underfloor heating (including heated basement rooms): 230 m² (2476 sq ft)
We can only install an air-to-water heat pump since drilling is not allowed, there is no gas supply line, and there is no space for a tank (pellets, oil, or gas).
Our preferred heating contractor has proposed the following system:
- Remko Monoblock LWM 150 10 – 13 kW
- Buffer tank PSFW 500
o (He argues that 500 L (132 gallons) should be enough and that the system can heat up hot water faster.)
- Fresh water module FWS Easy 30
o The flow rate of 30 L/min (8 gallons/min) is only specified at 70°C (158°F) supply temperature. We are not sure how it will perform with a buffer tank temperature of about 50°C (122°F).
Additionally, we will install about 7 kW photovoltaic (PV) modules on our south-facing roof. We want to either use the generated electricity to power the heat pump or run an electric heating element in the buffer tank, which would heat the tank to a set maximum temperature without using the heat pump. Otherwise, we aim to cover household electricity consumption as efficiently as possible.
Here are my questions for the experts among you:
1. Is the heat pump oversized? Initially, we were planning on a heat pump around 8 kW.
2. Would you use the electricity generated by the PV system to run the heat pump or the electric heating element?
3. How large should the buffer tank be? Is 500 L (132 gallons) too small, or does faster heating of 500 L outweigh the larger storage capacity of an 800 L (211 gallons) tank?
4. What type of buffer tank would you recommend in this case?
5. What do you think of fresh water modules? Would simultaneous showering be possible with this relatively small fresh water module?
a. A rainforest shower and handheld shower use 16 L/min (4.2 gallons/min) each without Eco mode, and 9 L/min (2.4 gallons/min) with Eco mode. What are your thoughts on Eco variants? Besides sustainability, we of course also see the advantage of lower water consumption.
b. The faucet we have chosen uses a maximum of 5 L/min (1.3 gallons/min).
Many thanks in advance!
We are very much looking forward to your assessments.
My girlfriend and I want to fulfill our dream of owning a home in the form of a semi-detached house built to KFW 55 energy efficiency standards, and we have a few questions regarding our heating system.
First, some basic information:
Currently a 2-person household; planned to be a 4-person household in the future
Basement + 2 full floors + occupied attic
Total house area: 267 m² (2873 sq ft)
Heated area with underfloor heating (including heated basement rooms): 230 m² (2476 sq ft)
We can only install an air-to-water heat pump since drilling is not allowed, there is no gas supply line, and there is no space for a tank (pellets, oil, or gas).
Our preferred heating contractor has proposed the following system:
- Remko Monoblock LWM 150 10 – 13 kW
- Buffer tank PSFW 500
o (He argues that 500 L (132 gallons) should be enough and that the system can heat up hot water faster.)
- Fresh water module FWS Easy 30
o The flow rate of 30 L/min (8 gallons/min) is only specified at 70°C (158°F) supply temperature. We are not sure how it will perform with a buffer tank temperature of about 50°C (122°F).
Additionally, we will install about 7 kW photovoltaic (PV) modules on our south-facing roof. We want to either use the generated electricity to power the heat pump or run an electric heating element in the buffer tank, which would heat the tank to a set maximum temperature without using the heat pump. Otherwise, we aim to cover household electricity consumption as efficiently as possible.
Here are my questions for the experts among you:
1. Is the heat pump oversized? Initially, we were planning on a heat pump around 8 kW.
2. Would you use the electricity generated by the PV system to run the heat pump or the electric heating element?
3. How large should the buffer tank be? Is 500 L (132 gallons) too small, or does faster heating of 500 L outweigh the larger storage capacity of an 800 L (211 gallons) tank?
4. What type of buffer tank would you recommend in this case?
5. What do you think of fresh water modules? Would simultaneous showering be possible with this relatively small fresh water module?
a. A rainforest shower and handheld shower use 16 L/min (4.2 gallons/min) each without Eco mode, and 9 L/min (2.4 gallons/min) with Eco mode. What are your thoughts on Eco variants? Besides sustainability, we of course also see the advantage of lower water consumption.
b. The faucet we have chosen uses a maximum of 5 L/min (1.3 gallons/min).
Many thanks in advance!
We are very much looking forward to your assessments.
D
Daniel-Sp5 May 2021 20:57Is there a heating load calculation? The proposed heat pump seems much too large.
500-liter (130-gallon) buffer tank? How is it integrated, and what does it buffer—domestic hot water, heating water, combined buffer, or a separation buffer?
Is there a proper calculation for the underfloor heating, or is it simply installed based on the usual "we always do it this way" approach?
How many heat pumps has the heating installer already installed? Any references?
Why use the electric heating element when the heat pump can utilize self-produced electricity with a better efficiency than any heating element in the world?
500-liter (130-gallon) buffer tank? How is it integrated, and what does it buffer—domestic hot water, heating water, combined buffer, or a separation buffer?
Is there a proper calculation for the underfloor heating, or is it simply installed based on the usual "we always do it this way" approach?
How many heat pumps has the heating installer already installed? Any references?
Why use the electric heating element when the heat pump can utilize self-produced electricity with a better efficiency than any heating element in the world?
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