Heat exchanger
A heat exchanger including a plurality of flat sheets arranged in parallel and a plurality of profiled sheets, each of which including a number of straight segments and being arranged between two subsequent flat sheets and having a repeating profile. The profiled sheets and the flat sheets together create a plurality of parallel ducts arranged in layers. The parallel ducts are divided by the profiled sheets into ducts of a first type and ducts of a second type, the ducts of the second type neighboring the ducts of the first type. Each duct of the first and second type has a width w(d) which is a function of a distance d with d the distance from a first flat sheet.
1. A heat exchanger comprising a plurality of flat sheets arranged in parallel and a plurality of profiled sheets, each of the plurality of profiled sheets being arranged between two subsequent flat sheets of the plurality of flat sheets and having a repeating profile, and each of the plurality of profiled sheets comprising only straight segments,
the profiled sheets and the flat sheets together creating a plurality of parallel ducts arranged in layers, the parallel ducts being divided by the profiled sheets into ducts of a first type and ducts of a second type, the ducts of the second type neighboring the ducts of the first type,
wherein each duct of the first and second type has a width w(d) which is a function of a distance d with d the distance from a first flat sheet of the plurality of flat sheets, wherein
a first region of the width is determined by the formula w(d)=c1*d when 0≤d≤d1,
a second region of the width is determined by the formula w(d)=c1*d1+c2*(d−d1) when d1≤d<d2, and
a third region of the width is determined by the formula w(d)=c1*d1+c2*(d2−d1)+c3*(d−d2) when d2≤d<d3
in which d3 is a distance between the first flat sheet and a subsequent flat sheet of the plurality of flat sheets, and wherein d1, d2, c1, c2, c3 are constant values, wherein c2≠c1,c3, and wherein 0<d1<d2<d3.
2. The heat exchanger according to claim 1 , wherein −2≤c2<5.
3. The heat exchanger according to claim 2 , wherein −0.3≤c2<0.3.
4. The heat exchanger according to claim 1 , wherein 0.1≤c1,c3≤5.
5. The heat exchanger according to claim 1 , wherein a cross section of each duct is symmetrical with reference to a perpendicular of the flat sheets.
6. The heat exchanger according to claim 1 , wherein the plurality of parallel ducts formed by the flat sheets and the profiled sheets are non-symmetrical in cross section of a layer of the heat exchanger.
7. The heat exchanger according to claim 1 , wherein c2=0.
8. The heat exchanger according to claim 1 , wherein c2<c1,c3.
9. The heat exchanger according to claim 1 , wherein at least the profiled sheets are formed from thermally deformable plastic.
10. The heat exchanger according to claim 1 , wherein 1 mm<d3<10 mm.
11. The heat exchanger according to claim 1 , wherein c1=c3.
12. The heat exchanger according to claim 1 , wherein d1=d3−d2.
13. A method of operating a heat exchanger, the method comprising:
providing a heat exchanger comprising a plurality of flat sheets arranged in parallel and a plurality of profiled sheets, each of the plurality of profiled sheets being arranged between two subsequent flat sheets of the plurality of flat sheets and having a repeating profile, and each of the plurality of profiled sheets comprising only straight segments, and the profiled sheets and the flat sheets together creating a plurality of parallel ducts arranged in layers, the parallel ducts being divided by the profiled sheets into ducts of a first type and ducts of a second type, the ducts of the second type neighboring the ducts of the first type,
wherein each duct of the first and second type has a width w(d) which is a function of a distance d with d the distance from a first flat sheet of the plurality of flat sheets, wherein
a first region of the width is determined by the formula w(d)=c1*d when 0≤d<d1,
a second region of the width is determined by the formula w(d)=c1*d1+c2*(d−d1) when d1≤d<d2, and
a third region of the width is determined by the formula w(d)=c1*d1+c2*(d2−d1)+c3*(d−d2) when d2≤d<d3
wherein d3 is a distance between the first flat sheet and a subsequent flat sheet of the plurality of flat sheets, and wherein d1, d2, c1, c2, c3 are constant values, wherein c2≠c1,c3, and wherein 0<d1<d2<d3;
leading a fluid of a first type through the ducts of the first type; and
leading a fluid of a second type through the ducts of the second type.
14. The heat exchanger according to claim 1 , wherein each of the plurality of parallel ducts comprises a rectangular shaped part and at least two triangular shaped parts.
15. The heat exchanger according to claim 1 , wherein each transition at each of the ducts of the first type to each of the ducts of the second type at each of the plurality of flat sheets is formed by a bend or fold in the plurality of profiled sheets forming an angle between adjacent ones of the straight segments such that a single point of contact is provided at each interface between the plurality of profiled sheets and one of the plurality of flat sheets.
16. The heat exchanger according to claim 1 , wherein the width w(d) of each duct of at least the first type increases linearly from 0 to d1, increases linearly from d1 to d2, and increases linearly from d2 to d3.
17. The heat exchanger according to claim 16 , wherein an amount of the linear increase in the width w(d) from each of 0 to d1 and d2 to d3 is greater than an amount of the linear increase in the width w(d) from d1 to d2.